Portable system for assisting body movement

ABSTRACT

The present invention provides a differential pressure body suit with external support against body suit migration. In its preferred embodiment, such body suit may comprise a close-fitting, multi-layered suit sealed against a mammal&#39;s skin to contain the differential pressure, or a looser-fitting suit that bends at the mammal&#39;s joints with minimal force. External support means include either fixed or movable mechanical supports attached to the body suit, extraordinary air pressure levels for making the body suit rigid, or exoskeletons attached to the body suit. A cyclic control system can turn the differential pressure condition within the body suit on and off on a selective basis to accommodate the movement of the legs of the mammal. The pressurization reduces the weight of the body to greater or lesser extents, and offloads the weight to the ground through the external support means.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application U.S. Ser. No.12/456,196 filed on Jun. 12, 2009, which is a continuation-in-part ofU.S. Ser. No. 12/319,463 filed on Jan. 7, 2009, which claims the benefitof U.S. provisional application Nos. 61/010,034 filed on Jan. 7, 2008,and 61/131,919 filed on Jun. 13, 2008, all of which are herebyincorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates generally to the motion and physical health ofthe mammalian body, and more specifically to portable systems forassisting humans or other animals to medically rehabilitate or trainspecific body parts through the application to such body parts ofdifferential pressure.

BACKGROUND OF THE INVENTION

Vertebrate animals feature a flexible, bony skeletal framework thatprovides the body shape, protects vital organs, and enables the body tomove. The human skeleton comprises approximately 206 separate bones.These bones meet at joints, the majority of which are freely movable.The skeleton also contains cartilage for elasticity, and muscularligaments consisting of strong strips of fibrous connective tissue forholding the bones together at their joints.

The femur, fibula, tibia, and metatarsal bones of the legs and feetsupport the body and therefore bear its weight. Muscles associated withthe ilium, pubis, ischium, patella, tarsal, and phalanges bones providethe necessary bending of the hips, knees, ankles, and toes that areessential for humans to walk, run, climb, and engage in other locomotionactivities.

Likewise, the humerus, ulna and radius bones and metacarpal andphalanges bones form the arms and hands, respectively. Musclesassociated with the clavicle, scapula, and carpals enable the arm tobend or flex at the shoulder or elbow, and the hand to flex at the wristand fingers, which is useful for lifting, carrying, and manipulatingobjects.

Over time, body bones or joints can become damaged. Bones fracture;ligaments tear; cartilage deteriorates. Such damage may result from theaging process, manifested by arthritis, osteoporosis, and slips andfalls. But injuries are also caused by sports activities. For example,recreational and competitive running is enjoyed by some 37 millionAmericans with 25% of them suffering from running injuries annually.Meanwhile, 57 million Americans bicycle for recreational ortransportation purposes. In addition to bodily injuries caused by falls,prolonged bicycling can result in groin discomfort or numbness. Thismedical injury is caused by the horn of the bicycle saddle creatingpressure points that can occlude the arteries and veins that supplyblood flow to the genitals. Within the 1999-2004 time period, 21publications within multiple medical specialties (e.g., sexual medicine,urology, neurology, cardiology, biomedical engineering, sports medicineand emergency medicine) established a clear relationship between bicycleriding and erectile dysfunction (“ED”).

A number of different approaches have been taken within the industry andthe medical community for preventing or treating these injuries.Exoskeletons entail external support systems made from strong materialslike metal or plastic composite fibers shaped for supporting properposture of the human body. Honda Motor Co. has employed “walking assistdevices” for its automotive factory workers to support bodyweight forreducing the load on assembly line workers' legs while they walk, moveup and down stairs, and engage a semi-crouching position throughout awork shift. The U.S. military has experimented with exoskeletons for itssoldiers to enable them to carry heavy equipment packs and weapons.However, the body must be connected to the exoskeleton at the limbs andother parts by means of straps and other mechanical attachment devices.The exoskeleton's motor must be regulated by various sensors andcontrols, and driven by hydraulics, pneumatics, springs, or othermotorized mechanical systems. These can be cumbersome and expensivesystems that do not necessarily reduce the stress on the body caused bygravity.

Athletes and older people suffering from joint injuries haverehabilitated in pools and water tanks. The buoyant property of thewater provides an upwardly-directed force to the body that lightens theload otherwise directed to the joints. However, these types of systemsare not portable, since the person is confined to the pool or watertank. Moreover, pools or water tanks may be unavailable or expensive toinstall.

Another approach is provided by a harness system exemplified by U.S.Pat. No. 6,302,828 issued to Martin et al. Consisting of an overheadframe to which is connected a raiseable body harness, such a systemsupports a portion of a person's body weight as he, e.g., walks or runson a treadmill in order to diminish downward forces on the body joints.But the straps and attachment devices create localized pressure pointsand stresses on the body, and restrict the range of motion of the bodyand its limbs. Such a mechanical weight off-loading system may also lackportability.

The National Aeronautics and Space Administration (“NASA”) has developeda system that utilizes differential air pressure to provide a uniform“lift” to the body to assist the exercise process. See U.S. Pat. No.5,133,339 issued to Whalen et al. The differential pressure is appliedto the lower half of the person's body that is sealed within a fixedchamber to create a force that partially counteracts the gravitationalforce on the body. A treadmill contained within the sealed chamberallows the person to exercise. However, this Whalen system requires alarge, immobile pressure chamber containing a treadmill. Such a systemis expensive and requires cumbersome entry and exit by the person. Itwill not enable the person any other means of exercise besides thetreadmill.

Pressurized bodysuits have also been used within the industry forseveral different applications. For example, U.S. Published Application2002/0116741 filed by Young discloses a bodysuit with integral supportsand internal air bladders that are filled with pressurized air. This airpressure exerts force against the muscles of a person wearing the suitto tone them during daily activities. U.S. Pat. No. 6,460,195 issued toWang illustrates exercise shorts with buckled belts, air bags, and avibrator that directs pulses of pressurized air to the body to work offfat and lift the hips. U.S. Pat. No. 3,589,366 issued to Feather teachesexercise pants from which air is evacuated, so that the pants cling tothe body of an exerciser to cause sweating, thereby leading to weightloss.

The U.S. military has also employed pressurized suits of various designsfor protecting fighter pilots from debilitating external G-forces. Dueto rapid changes in speed and direction, the fighter pilot's bodyundergoes very high accelerations. This normally forces the pilot'soxygen-laden blood away from the portion of the circulatory systembetween the heart, lungs and brain, pooling instead toward the bloodvessels of the lower extremities. As a result, the pilot can losesituational awareness and spatial orientation. A pilot's bodysuitpressurized against the blood vessels of the legs can force theoxygen-laden blood back to the head and torso of the pilot. See U.S.Pat. No. 2,762,047 issued to Flagg et al.; U.S. Pat. No. 5,537,686issued to Krutz, Jr. et al.; and U.S. Pat. No. 6,757,916 issued to Mahet al. U.S. Pat. No. 5,997,465 issued to Savage et al. discloses a pantsbodysuit made from metal or polymer “memory material” that is heated byelectrical current to form around the body, and then cooled to applypressure for treating this G-forces phenomenon.

Pressurized bodysuits have been used previously for other purposes, suchas splinting leg fractures, stopping bleeding from wounds, treatingshock, and supporting the posture of partially paralyzed patients. See,e.g., U.S. Pat. No. 3,823,711 issued to Hatton; U.S. Pat. No. 3,823,712issued to Morel; U.S. Pat. No. 4,039,039 issued to Gottfried; and U.S.Pat. No. 5,478,310 issue to Dyson-Cartwell et al. Bodysuits can alsohave air between the suit and the body evacuated by vacuum to draw thesuit into close contact with the body. See U.S. Pat. No. 4,230,114issued to Feather; U.S. Pat. No. 4,421,109 issued to Thornton; and U.S.Pat. No. 4,959,047 issued to Tripp, Jr. See also U.S. PublishedApplication 2006/0135889 filed by Egli.

Such pressurized body suits have not previously been used torehabilitate skeletal joint injuries or minimize conditions that causeerectile dysfunction. Moreover, they have typically been used only instationary situations like a sitting pilot due to the problem of airpressure forcing the body suit off the lower torso. In some applicationslike weight-loss patients, suspender straps have been required toovercome this downwards migration of the bodysuit pants.

Thus, a pressurized bodysuit that can be used to apply localizeddifferential pressure to a lower or upper body part for injuryrehabilitation or minimization, coupled with an external support orpressure condition control system would be beneficial, particularly dueto its portable nature. Such a pressurized body suit system could beworn by a patient, athlete, or other person within a variety of settingsto perform a variety of different functions.

SUMMARY OF THE INVENTION

The present invention provides a differential pressure body suit withexternal support against body suit migration. In its preferredembodiment, such body suit may comprise a close-fitting, multi-layeredsuit sealed against a mammal's skin to contain the differentialpressure, or a looser-fitting suit that bends at the mammal's jointswith minimal force. External support means include either fixed ormovable mechanical supports attached to the body suit, extraordinary airpressure levels for making the body suit rigid, or exoskeletons attachedto the body suit. A cyclic control system can turn the differentialpressure condition within the body suit on and off on a selective basisto accommodate the movement of the legs of the mammal. This differentialpressure body suit provides a portable and convenient system forrehabilitating a skeletal joint injury or training the mammal for injuryprevention, athletic performance, or fat reduction, or assisting themobility of the physically disabled. The pressurization reduces theweight of the body to greater or lesser extents, and offloads the weightto the ground through the external support means. The body suit isflexible and has joints that can flex with minimal force even underpressure.

The invention can also be used to assist the mobility for, e.g., theelderly or disabled people, who have common problems such asdegenerative hips or knees by reducing the stress on their joints.Furthermore, the alternating pressure/depressurization cycle can providemedical benefits via the body suit similar to massage, or by enhancingvenous return of blood to the heart for, e.g., people suffering fromvaricose veins or other vascular disorders. The system can alsofacilitate proper posture, and avoid bed sores caused by prolongedhorizontal contact by the body with the bed. This is not a purelymechanical system for supporting bodily motion, such as an exoskeleton.This invention is useful not only for humans, but also for other animalslike dogs, cats, and horses.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a perspective view of the assisted motion system of thepresent invention.

FIG. 2a is a schematic view of the legs and feet of a human and theforces applied thereto.

FIG. 2b is a schematic view of a body suit of the present invention andthe forces applied thereto.

FIG. 3 is a cut-away view of the body suit.

FIG. 4 is a schematic view of the construction of the body suit.

FIG. 5 is a partial view of the body suit connected to a portion of theexternal support frame.

FIG. 6 is a partial front view of a waist seal attached to the interiorof the body suit.

FIG. 7 is a cut-away front view of an alternative airtight shortsembodiment of a waist seal for the body suit.

FIG. 8 is a cut-away front view of an inflatable air tube seal for thebody suit.

FIG. 9 is a perspective view of a human wearing a full-length pants bodysuit of the present invention.

FIG. 10 is a perspective view of a human wearing a pants body suit onlyextending to the ankles.

FIG. 11 is a cut-away view of a sleeve seal for the body suit of FIG.10.

FIG. 12 is a perspective view of a human wearing a pants body suit onlyextending to just above the knees.

FIG. 13 is a cut-away view of a sleeve seal for the body suit of FIG.12.

FIG. 14 is a schematic view of the body suit construction furthercomprising an airtight bladder sealing means.

FIG. 15 is a front partial view of the air bladder construction of FIG.14.

FIG. 16 is a side partial view of the air bladder construction of FIG.14.

FIG. 17 is a perspective view of an alternative embodiment of the bodysuit comprising separate pressurized leg units.

FIG. 18 is a partial perspective view of an alternative embodiment ofthe body suit comprising a circumferential tension system.

FIG. 19 is a perspective view of an alternative embodiment of the bodysuit comprising a loose-fitting body suit.

FIG. 20 is a perspective view of an external wheeled frame supportstructure for the body suit.

FIG. 21 is a perspective view of an external cart-like support structurefor the body suit.

FIG. 22 is a perspective view of a stationary support frame structurefor the body suit.

FIG. 23 is a partial perspective view of a constant-force adjustmentmechanism for the stationary support frame structure of FIG. 22.

FIG. 24 is a perspective view of an assisted motion system of thepresent invention for bicycle riders.

FIG. 25 is a front view of the support structure for the bicycleassisted motion system of FIG. 24.

FIG. 26 is a back view of the support structure for the bicycle assistedmotion system of FIG. 24.

FIG. 27 is a perspective view of the support structure shown in FIGS.24-26.

FIG. 28 is a perspective view of an external exoskeleton supportstructure for the body suit of the present invention.

FIG. 29 is a perspective view of an internal exoskeleton supportstructure for the body suit of the present invention.

FIG. 30 is a perspective view of pressurized body suit units whichprovide the support structure for the body suit.

FIG. 31 is a perspective view of a loose-fitting body suit of thepresent invention featuring a cyclic gas pressurization/depressurizationsystem for supporting the body suit.

FIG. 32 is a perspective view of a portable cyclic gaspressurization/depressurization system for supporting the body suit alsosupported by an external exoskeleton system.

FIG. 33 is a perspective view of the portable cyclic gaspressurization/depressurization system for supporting separatepressurized body units also supported by an external exoskeleton system.

FIG. 34 is a perspective view of a body suit for the upper body tomaintain its vertical posture.

FIG. 35 is a perspective view of a body suit for the upper body tomaintain its horizontal posture.

FIG. 36 is a perspective view of body suit vest for applying a negative(vacuum) pressure to the upper body.

FIG. 37 is perspective view of the body suit vest of FIG. 36 with anexternal wheeled support frame.

FIG. 38 is a perspective view of a body suit for a horse.

FIG. 39 is a front view of the body suit of FIG. 38.

FIG. 40 is a perspective view of the horse body suit of FIGS. 38-39 withan external wheeled cart support frame.

FIG. 41 is a perspective view of an elastic suspension system of thepresent invention.

FIG. 42 is a perspective view of a mobile walker support structure usedwith the pressurized suit invention.

FIG. 43 is a graphical representation of the experimental weight resultsof an individual wearing the pressurized body suit of Example 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A differential pressure body suit with external support against bodysuit migration is provided by the invention. In its preferredembodiment, such body suit may comprise a close-fitting, multi-layeredsuit sealed against a mammal's skin to contain the differentialpressure, or a looser-fitting space suit that bends at the mammal'sjoints with minimal force. External support means include either fixedor movable mechanical supports attached to the body suit, extraordinaryair pressure levels for making the body suit rigid, or exoskeletonsattached to the body suit. A cyclic control system can turn thedifferential pressure condition within the body suit on and off on aselective basis to accommodate the movement of the legs of the mammal.This differential pressure body suit provides a portable and convenientsystem for rehabilitating a skeletal joint injury or training the mammalfor injury prevention, athletic performance, or fat reduction, orassisting the mobility of the physically disabled. The pressurizationreduces the weight of the body to greater or lesser extents, andoffloads the weight to the ground through the external support means.The body suit is flexible and has joints that can flex with minimalforce even under pressure. The invention can also be used to assist themobility for, e.g., the elderly or disabled people, who have commonproblems such as degenerative hips or knees by reducing the stress ontheir joints. Furthermore, the alternating pressure/depressurizationcycle can provide medical benefits via the body suit similar to massage,or by enhancing venous return of blood to the heart for, e.g., peoplesuffering from varicose veins or other vascular disorders. This is not apurely mechanical system for supporting bodily motion, such as anexoskeleton.

For purposes of the present invention, “differential pressure” means thedifference in pressure conditions across opposite sides of the bodysuit, such as a positive pressure or negative (vacuum) pressurecondition contained inside the suit, and an atmospheric pressurecondition on the outside of the suit. For example, if atmosphericpressure is equal to 14.7 lbs/in² (“psi”), and the internal pressurizedcondition of the body suit is 15.7 psi, then the differential pressureapplied by the body suit to the mammal wearing the body suit is 1.0 psi.Such differential pressure can also be represented as ΔP within thisapplication.

As used within this application, “positive pressure” means any pressurelevel in excess of atmospheric pressure.

For purposes of this application, “negative pressure” means any pressurelevel less than atmospheric pressure. A vacuum is an example of such anegative pressure. Partial vacuums are also covered by this invention.

In the context of the present invention, “body portion” means any partof the body to which the differential pressure condition is applied bythe body suit. Examples include, without limitation, feet, legs, knees,hips, shoulders, arms, elbows, torso, and the back.

As used within this application, “body suit” means a single ormulti-layered, close-fitting or loose-fitting suit capable of containinga positive or vacuum pressure condition that covers a predetermined bodyportion. Examples include, without limitation, trunks, shorts,full-length pants, such pants that cover the feet, shirts, and chest orarm segments. The suit is provided with a means for creating thepositive or negative (vacuum) pressure condition within the suit. Such ameans may be a port connected to an air pressure control system.

In the context of the present invention, “pressure-tight” means withrespect to the body suit that the material forming such body suit iscapable of containing a positive or negative pressure condition withoutsubstantial diminishment over a time period that is relevant to theusage of the body suit. Thus, pressure tightness does not require anabsolute absence of any loss of pressure or vacuum, nor does it requiremaintenance of the positive pressure or vacuum condition within the suitfor a time period greater than the time interval during which the suitis worn for an exercise or therapeutic treatment session, or beyondwhich such positive pressure or vacuum condition can reasonably bereplenished within such exercise or therapeutic session.

For purposes of the present invention, “mammal” means any of a class ofhigher vertebrates comprising humans and all other animals that nourishtheir young with milk secreted by mammary glands, and have the skinusually more or less covered with hair. Such animals include, withoutlimitation, horses, dogs, and cats.

A human runner will be used as an exemplary mammal for purposes ofdescribing the assisted motion system of the present invention. It isimportant to appreciate, however, that any other type of mammal for anyother kind of exercise, life activity, or rehabilitative activity iscovered by this application, as well.

The assisted motion system 10 of the present invention is shown inFIG. 1. Unlike prior art static systems that require a runner to use astationary treadmill, this system is portable, thereby enabling therunner 12 to enjoy exercising outdoors on the road or a trail. In thisembodiment, the runner wears a differential pressurized pant suit 14that extends downwardly from the runner's waist 16 and covers the feet18. The runner's legs 20 are depicted inside the differentialpressurized suit 14 in broken lines 22.

The differential pressurized suit 14 is constructed of air-tightmaterial, and affords easy movement by the body and limbs of runner 12while running. The suit 14 is sealed against the body at the waist 16.When air pressure condition P above atmospheric pressure P_(atm) isadded to the volumetric region 24 defined between the runner's legs 20and the suit 14, a differential pressure condition ΔP is created inwhich the runner's lower body portion contained within the suit 14experiences a higher pressure condition than the runner's upper body 26,which only experiences P_(atm). Due to this pressure differential ΔP, anupwards force is exerted on the runner 12 by the higher air pressurecontained inside the suit 14, thereby acting to diminish the weight ofthe runner's body. Runner 12 thereby experiences a reduced weight on hisfeet, knees, legs, and lower body when he runs in this differentialpressurized suit 14, compared with if he ran without the suit.

FIG. 2 illustrates the various vector forces on the runner's body. Therunner 12 and the differential pressurized suit 14 are depictedseparately in FIGS. 2a and 2b , respectively, for ease of understanding.The force from gravity exerted on the runner's body mass is shown asF_(g). In use, the suit 14 is sealed to the runner's body at the waist16, and pressurized to pressure P to create the differential pressurecondition ΔP between the upper and lower bodies. The cross-sectionalarea of the body at waist 16 is depicted as area A_(w). The positivepressure P is directed against the body and legs 20. The differentialpressure condition ΔP results in an upwards-directed resultant forceF_(b) on the body located at the centroid 17 of cross-sectional areaA_(w). This total upwards force F_(b) is:F _(b) =ΔP×A _(w)This constitutes the amount of weight that is effectively reduced fromthe lower body 20 of runner 12. For example, a runner experiencing apressure differential ΔP on the lower body of 0.5 psi having across-sectional waist area of A_(w) of 100 square inches wouldexperience a 50 lb reduction in weight due to the differentialpressurized suit 14.

FIG. 2b illustrates the various vector forces on the suit 14. Thecross-sectional area of the suit at waist 16 is depicted as A_(s). Inthe case of a closely-fitting body suit, A_(s) should approximate A_(w).The positive pressure differential ΔP also results in a downwardsdirected force F_(s) on the suit 14. The amount of this downwards forceF_(s) is:F _(s) =ΔP×A _(s).This constitutes the amount of force that pushes the suit down the body.For example, a suit pressurized to a pressure differential ΔP of 0.5 psihaving a cross-sectional waist area As of 100 square inches is subjectto a 50 lb downwards force. This force F_(s) would ordinarily cause suit14 to work its way downwardly along legs 20. Therefore, an importantpart of the invention is the inclusion of external support 26 to preventthe downward migration of the suit. In the case of the embodimentdepicted in FIG. 1, external support 26 constitutes a frame 28 that isoperatively connected to wheels 30. The suit is attached to the frame 28at attachment points 29. When the differential pressurized suit 14 isconnected to frame 28, the downward force F_(s) exerted on the suit 14is matched by the upwards reaction force exerted by the supportingstructure at the attachment points 32.

In this manner, the supported differential pressurized suit 14 is ableto diminish the weight of the runner's body without contacting the body.Through the application of differential pressure ΔP, an amount of weightΔW of the body equal to:ΔW=W−(ΔP×A _(w))is transferred from the muscle-skeletal structure of the runner's lowerbody to the support structure 28 of the external support 26, and throughthe support structure 28 and wheels 30 to the ground. Moreover, thesupport structure prevents force F_(s) from pulling the differentialpressurized suit 14 off runner 12. Furthermore, because the wheel-basedsupport structure 26 and differential pressurized suit 14 are completelyportable in nature, runner 12 can go anywhere with the motion-assistedsystem 10, instead of being confined to a stationary or pressurechambers as with prior art systems.

When the runner's body is in contact with the ground via feet 18,various amounts of weight can be effectively removed from the body,depending upon the level of positive pressure P introduced to the bodysuit. For example, for a 180 lb runner having a cross-sectional areaA_(w) of 100 square inches, a differential pressure ΔP of 1 psi wouldreduce his weight by 100 lbs. The runner's lower body would thereforeonly need to support a weight of 80 lbs. A 0.5 psi pressure differentialΔP would take off 50 lbs of weight. A 0.25 psi pressure differentialwould take off 25 lbs of weight.

The preferred construction of differential pressurized suit 14 is shownin greater detail in FIGS. 3-4. Close fitting suits provide theadvantage of greater mobility for runner 12. Suit 14 is constructed fromat least three layers of material. FIG. 3 shows a cut-away view of thesuit illustrating its different layers.

An air-tight inner layer 31 featuring an airtight seal 32 at the waist16 of the runner's body maintains the positive pressure P conditioninside the suit against the runner's body skin 34. The fabric for thisair-tight layer which is closest to the body may be formed from anypressure-tight material that is also sufficiently flexible to affordmobility by the runner. Examples include, without limitation, latexrubber, neoprene, and air-tight elastic fabrics like latex-coated Lycra.This fabric should be sufficiently thin and elastic to provide comfortwithout restriction. Preferably, suit 14 is about 0.002-0.040 inchthick, more preferably about 0.005-0.015 inch thick, still morepreferably about 0.010 inch thick. The elasticity of the material can beexpressed by spring rate, which is the force necessary to double aone-inch-thick strip of fabric. Preferably, this spring rate should beabout 0.2-2.0 lbs, more preferably about 0.5-1.5 lbs, still morepreferably about 1.0 lb.

Two outer layers 36 and 38 of the differential pressurized suit 14composition prevent the suit from expanding due to the force applied bypositive pressure P, while maintaining the shape of the suit to fitclosely to the body. This close fit provides for ease of mobility of thebody and its limbs. It also prevents the legs of the suit fromcontacting each other during the running motion. Moreover, this closefit of the suit reduces the volume of pressurized air or other suitablegas in contact with the body joints in order to facilitate bending ofthe legs.

The fabric for these first and second outer layers 36 and 38 should becomposed of mesh, netting, or other suitable fabric. Suitable meshmaterial is available from Apex Mills Corporation of Inwood, N.Y. Thismesh or netting is constructed to mostly be non-extending along oneaxis, and elastic or extensible along a second axis perpendicular to thefirst axis. Exemplary mesh materials include, without limitation,nylon-Lycra that can be knit or braided, or a monofilament like nylon orDacron.

The first outer layer 36 serves to prevent the suit 14 from expandingcircumferentially. The circumferential direction of expansion isperpendicular to the longitudinal axis of the legs and body fabric. Thefabric is oriented so that its non-extending axis follows thisdirection. The fabric can be more specifically oriented so that itsnon-extending axis follows lines on the body in which the skin does notstretch or extend during bending or other movement. These lines areknown within the industry as “lines-of-non-extension.” Lines ofnon-extension run both parallel and perpendicular to the longitudinalaxis of the legs and body. This first layer of fabric preferably wouldfollow the perpendicular lines of non-extension.

The second outer layer 38 serves to prevent the suit 14 from expandinglongitudinally under pressure. This fabric layer is oriented, so thatits axis of non-extension generally follows lines that are generallyparallel to the longitudinal axis of the legs and body. Preferably, thefabric can be more specifically oriented in this direction to followlongitudinal lines on the body in which the skin does not stretch orextend during bending or other movement. Where appropriate in sectionsof the body which do not flex, such as the thigh area or lower calves,cloth, mesh, or net material that is non-extendible along both axes maybe used. This second outer fabric layer 38 which is mostlynon-extensible in the vertical direction of an upright body effectivelycarries the vertical downward load on the suit resulting from thepositive pressure differential.

Differential pressurized suit 14 may also feature additional layers ofnylon 40 between the body 20 and the air-tight inner layer 30, and 42and 44 between the inner 30 and first outer layer 36, and two outerlayers 36 and 38, respectively, in order to enable the suit and layersto slip relative to one another on the body to improve the runner'smobility. Air-tight zippers 46 positioned along the suit 14 near itswaist 16 and feet 18 portions allow for easy entry and removal of thesuit. Such air-tight zippers are available from YKK (U.S.A.) Inc. ofMarietta, Ga. Moreover, the suit 14 may feature an inner vent layer 48that provides airflow and moisture control. In other embodiments theselayers can be separately combined into a single layer that provides thesame basic functioning as for the separate layers described above.

As shown in FIG. 5, a band 54 serves to attach the suit 14 to thesupporting structure 28. This band is attached to the supportingstructure with a fitting 29, such as a threaded collar receivingthreaded ends extending from support structure 28. The band shouldconform to the generally elliptical shape of waist cross-section A_(w)that surrounds the suit 14 at the waist 16. This band serves anadditional purpose of containing the outward pressure force in order toenhance the radial inward force as the suit is filled with pressure.This assures that the suit will conform closely to the body at the waist16.

The band 54 may be made from any suitable material that is strong enoughto contain this outwardly-directed force, including metal, plastic, orcomposites. It may be made moldable to the general shape of the runner'swaist, using a thermoset plastic material. The band 54 may alternativelybe formed from a strong, flexible fabric, such as nylon. The suit 14 maybe attached and detached from the band 54, using a Velcro fasteningsystem. Other mechanical fastening systems such as straps, snaps, orhooks engaging eyelets may also be utilized. Alternatively, the band canconstitute an integral part of the suit. The band may be in two pieceshinged and fitted with a locking clasp to allow for easy entry.

In the embodiments of the differential pressurized suit 14 shown inFIGS. 1-3, the suit covers the entire lower legs and feet, so that theentire lower body below the waist is airtight. A seal 40 is connected tothe waist of suit 14 with an airtight connection, so that air pressurecannot escape between the suit and the seal. While the seal 40 may bepositioned at the waist area, it may also be located lower, below thehips, or somewhere in between.

The seal 40 constitutes an airtight band of material that fits tightlyover the body. As shown more clearly in FIG. 6, it is attached to thesuit 14 at 55. This seal 40 is preferably constructed of elasticneoprene, or any other airtight material, such as rubber, latex, or arubber-coated Lycra. Suitable latex rubber sheeting is available fromRubber Cal of Santa Ana, Calif. The seal should be sufficiently wideacross the waist area of the suit to provide for a sufficient airtightclosure. The circumference of the seal 40 should be less than theunstretched circumference of the body part that is circumscribed by theseal, so that when the seal 40 is secured around the body part (in thiscase, the waist area), a positive pressure is applied by the seal to theunderlying skin. Combined with the air at pressure P that is introducedinto the suit 14 within the volume between the suit's airtight innerlayer 30 and the runner's body skin, the suit 14 and associated seal 40maintain a relatively airtight seal in order to confine the volume ofair pressure P inside the suit. The seal 40 is sufficiently airtightthat it provides enough sealing force to maintain the air pressureinside the suit using the air control system.

FIG. 7 shows another embodiment of a waist seal for suit 14. In anotherembodiment of the differential pressurized suit 14 of the presentinvention, the waist seal can comprise an airtight pair of shorts 53that are connected to the interior of the suit. Such shorts can betight-fitting, airproof neoprene compression shorts that provide a tightfit against the body. These shorts can be connected to the suit at thewaist by means of an airproof zipper. The shorts can also consist of atight-fitting, breathable fabric that has a band of airproof latex orrubber coating at the top or bottom portion to provide the airproof sealagainst the body.

In yet another alternative embodiment, the seal can consist of aninflatable air tube seal 50, as shown in FIG. 8. This inflatable tubeseal circumscribes the waist, and is attached via an airtight connectionto the exterior of the suit. When inflated with air, the tube seal 50expands and applies an inwardly directed force to the waist to compressit against the skin to confine the air pressure P condition inside thesuit.

As shown in FIG. 9, when suit 14 is pressurized, it maintains a shapeclose to the body, while affording mobility of the body and limbs. Aport 56 is provided in the suit to allow for pressurizing anddepressurizing the suit. An air control system 58 connected to anassociated pressurized air source 59 maintains the positive pressurecondition P inside the suit. The air control system 58 may also controlthe humidity and temperature levels existing inside the suit. The suitmay be statically pressurized once, and then worn by the person withoutthe control system 58. When operating in this manner, the seal 40maintains the pressure condition for the duration of the time periodthat the suit is worn. The suit may be worn for time periods rangingbetween minutes for brief exercises to days for medical rehabilitation.

While this application discusses the use of pressurized air to fill thesuit, other pressurized gases may be employed. Other examples of suchpressurized gases include nitrogen, carbon dioxide, and argon. Suchgases must be non-toxic and not harmful to body skin, or else an innerlayer must be worn between the gas and the skin to protect the skin andbody.

The differential pressurized suit 52 shown in FIG. 9 comprises afull-length pair of pants which also completely cover the feet. Airtightzippers 60 assist entry into the waist region of the pants. Airtightzippers 62 do the same for ankle regions. Finally, airtight zippers 64allow the foot portion 66 of the suit 52 to be attached to the pantsportion 68 after the feet are inserted through the pant legs.

Still another embodiment of a differential pressurize suit 70 isdepicted in FIG. 10. In this particular embodiment, the suit extendsfrom the waist 72 to the ankles 74 without covering the feet, and issealed at the ankle. The waist seal is as described above, and mayinclude a rigid band 54 surrounding an air bladder. The ankle seals 76are shown in greater detail in FIG. 11, and comprise a sleeve seal 41connected inside the suit leg 70 that is constructed of elasticneoprene, or another airtight elastic material, such as rubber, latex,or a rubber-coated Lycra. The sleeve seal 41 can be a tight-fitting,airproof neoprene compression sleeve that provides a tight fit over theankle and lower calf. The sleeve seal 41 should be long enough toprovide for a sufficiently airtight closure between the seal and thebody skin. The unstretched circumference of the ankle sleeve seal 41should be less than the circumference of the ankle and lower calf, sothat when the sleeve seal 41 is secured around the ankle, a positivepressure is applied by the seal to the underlying skin by the elastictension of the seals. In this manner, when the suit is pressurized withair to pressure condition P, the pressurized air is substantiallycontained within the suit 70.

By having suit 70 end at the ankles, motion by the foot will not beimpaired by the foot portion of the suit. The suit 70 may also be put onmore easily. Moreover, the wearer may wear normal-sized shoes.

The net upward force provided by pressurized air contained within suit70 may be calculated as:F _(b) =ΔP(A _(w)−2A _(A))where ΔP is the difference in pressure level P inside the suit andatmospheric pressure P_(atm) outside the suit. A_(w) is thecross-sectional area of the waist. A_(a) is the cross-sectional area ofeach ankle.

Another embodiment of differential pressurized suit 80 is shown in FIG.12. In this embodiment, suit 80 extends to just above the knee. It issealed at the waist 82 and at the knees 84. The waist seal 86 is asdescribe above. The knee seals 88 are shown in greater detail in FIG.13. The sleeve seal 81 is an airtight sleeve connected to the interiorof the suit 80 that fits tightly over the lower thigh. The sleeve sealshould be long enough to provide for a sufficiently airtight closure.The circumference of the knee sleeve seal 81 should be less than theunstretched circumference of the lower thigh, so that when the seal 81is secured around the knee, a positive pressure is applied by the sealto the underlying skin. This sleeve seal 81 is preferably constructed ofelastic neoprene, or any other air-tight material, such as rubber,latex, or rubber-coated Lycra. An advantage provided by this suit 80 isthat the runner's knee and lower leg are free to move without anyrestriction posed by suit 80. This suit 80 is also easier to put on andtake off.

The net upwards force supplied to the runner's body when suit 80 isfilled with pressurized air is:F _(b) =ΔP(Δ_(w)−2A _(k))ΔP is the difference in pressure between pressure condition P containedinside the suit 80 and atmospheric pressure P_(atm) existing outside thesuit 80. A_(W) is the cross-sectional area of the waist. A_(K) is thecross-sectional area of the spot on each leg just above the knee whereseals 88 engage the leg.

In another embodiment shown in FIG. 14, the pressurized air is containedwithin the body suit by means of an air-tight bladder 29 illustrated inan expanded view of the layers of the suit. The bladder consists of anairproof inner layer 31 and outer layer 33. The two layers are joined atthe top and bottom of the suit to form an air-tight bladder. Thisbladder is essentially two identical air-proof layers, nested one insidethe other, and sealed together at the top waist area and bottom of eachleg of the suit. When pressurized, the inner layer presses against theskin and the outer layer presses against the outer constraining layers36 and 38. A frontal view of the bladder 29 is shown in FIG. 15. A sideview of the bladder is shown in FIG. 16. The bladder 29 contains air atpressure condition P. The bladder may be used for the variousembodiments of the pressure suits described herein, including a bladderthat extends from the waist to around the foot, a bladder that extendsfrom the waist to the ankle, and a bladder that extends from the waistto above the knee.

Yet another embodiment is shown in FIG. 17 of differential pressurizedsuit 90. This embodiment consists of an independent suit 92 and 93 foreach leg, having leg openings 94 near the upper thigh. The upper thighseals 95 can extend diagonally from the upper thigh at the groin on theinner side of the leg to the hip on the outer side of the leg. A_(t) isthe cross-sectional area of the spot on each leg at the upper thighwhere seals 95 engage the leg.

Each leg suit 92, 93 covers the entire lower leg and foot, so that theentire leg below the thigh seal 95 is airtight. The leg suits areattached by means of straps 96 to a rigid band 98 that is provided nearthe waist. This band may alternatively constitute a strong, flexiblefabric. The band 98 is then attached to a supporting structure (notshown). Alternatively, the leg suits may be attached directly to thesupport frame by means of straps 96. The positive pressure differentialΔP contained in the leg suits 92, 93 results in an upwards-directedresultant force F_(b) applied to the body located at the centroid 97 ofthe cross-sectional area A_(t). The total amount of this upwards forceF_(b) on the body from both leg suits is:F _(b)=2ΔP×A _(t)where ΔP is the difference in pressure between the positive pressure Pcondition inside the suit and atmospheric pressure P_(atm) outside thesuit. A_(w) is the cross-sectional area of the waist region. A_(t) isthe cross-sectional area of each upper thigh region.

The various configurations of suits described above provide high tolower amounts of upwards force F_(b) on the body, depending upon thelocation of the seals. The complete lower body coverage suit 14 of FIG.1 provides the greatest upper lift to the body, because:F _(b) =ΔP×A _(w).The waist-to-ankle suit 70 of FIG. 10 provides the next largest amountof lift, because:F _(b) =ΔP(A _(w)−2A _(a)).Next in decreasing progression is the waist-to-just-above-the-knee suit80 of FIG. 12, because:F _(b) =ΔP(A _(w)−2A _(k)).For most humans, their body anatomy is such that A_(a)<A_(K). Theindependent leg suits 92, 93 also provide for a higher to lower amountof upwards force on the body. The leg suit with a top seal at the upperthigh of FIG. 17 provides the highest amount:F _(b)=2ΔP×A _(t).A leg suit with a top seal at the upper thigh and a bottom seal at theankle (not shown) provides the next highest amount:F _(b)=2ΔP×(A _(t) −A _(a)).A leg suit with a top seal at the upper thigh and a bottom seal at thespot above the knee (not shown) provides the lowest amount:F _(b)=2ΔP×(A _(t) −A _(k)).

While pressurized gases like air have been discussed as the pressurizingmedium for the differential pressurized suit 14 of this invention,positive pressure applied against a body and its limbs can be created byother means. For example a fabric or elastic material 102circumferentially kept under tension around a leg 104 can be employed,as depicted in FIG. 18. The material 102 exerts a tension T_(c) thatcreates an inwardly-directed radial force F_(r) on the body that isnormal to the surface of the leg. The effect of this force within thiscircumferential tension system 100 is similar to the effect of positivepressure developed by air pressure—i.e., a net upwards force is createdon the body.

Various means can be utilized to develop this tension. For example, anelastic material can provide this circumferential tension. In suchexample, the “suit” is constructed by a multitude of windings of anelastic material that is perpendicular in direction to the axis of theleg 104, and non-extensional in the longitudinal direction of the leg.The suit is sized to be smaller than the body, so that a tension isdeveloped when the suit is put on. Alternatively, the suit can be placedunder tension through the use of zippers, or by cinching up the suit vialacing, tied in a knot after it is put on. Suits of this circumferentialtension embodiment 100 may be similar in degree of coverage, asdiscussed above—e.g., waist-to-above-the-knee, waist-to-ankle,waist-to-around-foot; upper thigh/hip-to-above-knee; upperthigh/hip-to-above-ankle; upper thigh/hip-to-around-foot.

An air bladder 106 positioned under a portion of the wrap 102 againstthe leg 104 may be utilized to create further tension inside the suit100. This air bladder should have a small width, and extendlongitudinally along the body under the wrap 102. When the bladder 106is inflated with a gas like pressurized air, the wrap 102 is placedunder tension. Advantageously, only a small amount of air is required tocreate the positive pressure on the body, because the wrap 102, itself,also contributes positive pressure via the tension. At the same time,the wrap material can allow for breathability and the transfer ofmoisture away from the body.

Shaped memory alloys like nickel titanium or shaped polymers maylikewise be used to provide the tension in a circumferentially-tensionedpressure suit. An electric current can be applied to cause the materialto change in shape to conform to the underlying body's shape, and createcircumferential tension. Shaped memory alloys or polymers can be woveninto fabric that the suit is constructed of.

While close fitting differential pressure suits 14 andcircumferentially-tensioned suits 100 have been described for use withthe assisted motion system 10 of the present invention, a looser-fittingsuit 110 may also be employed, as shown in FIG. 19. The legs of the suit110 may extend downwardly to just above the knee, above the ankle, orcover the entire foot, as described above. Seals 112 can be providedaround the waist and at the bottom edges of the suit if the suit doesnot extend around the feet. Exemplary locations include: upper seals 112at the waist or upper-thigh-to-hip; lower seals at above the knee orabove the ankle.

Mobility of the body 114 and lower legs 116 is provided by constantvolume joints positioned at the waist 118, knee 120, and ankles 122,respectively, of the suit 110. The equation for work where volume ischanged under a constant pressure is:W=P×ΔVwhere W is work, P is the constant pressure, and ΔV is the change involume. Clearly, holding the volume constant in a joint, such that ΔV=0over the course of joint flexure is one way to nullify the need toexpand work just to flex the suit joint.

A constant-volume joint allows the cross-sectional area of the joint ofthe suit to maintain a constant volume of pressurized air P duringbending of the body, so that the work, and thus the force, required tobend the joint is minimized. In the preferred embodiment ofloose-fitting differential pressure suit 110, the constant volume jointsconsist of baffles and tensioning straps along the sides of the joint toprevent the baffles from extending. Other types of constant-volumejoints known in the prior art, such as “Space Suit Mobility Jointsdescribed in U.S. Pat. No. 4,151,612, and which is hereby incorporatedby reference in its entirety, may also be utilized. The suit shown inFIG. 19 has constant volume joints positioned at thewaist-through-the-hip section and at the knee. A constant volume jointat the knee 120 allows the leg to bend and move at the knee with themotion of walking or running without the need for undue force. Anairproof boot 124 is worn and the constant volume joint 122 is utilizedto allow for mobility.

Pressurized gas 126, such as air, is injected into the suit 110 by meansof control system 128 and hoses 129. A person wearing the suit 110 mayexercise on a treadmill 127, but portable pressurized gas systems arealso possible.

A rubberized nylon can be utilized to construct a single-layer suit.This can be sewn into the appropriate shape using a standard sewingmachine. Thigh seals can be made from a commercially-purchased neoprenecompression sleeve. Compression sleeves are available from AdvancedBrace of Irving, Tex. Neoprene compression shorts are available from thesame supplier. The compression sleeve can be sewn interior to the pantaround the thigh opening, and made airtight with seam sealer in the formof Seam Lock sold by REI, Inc. of Sumner, Wash. to make the seamairtight. A shorts-type waist seal can be constructed by sewing thewaist area to the outer rubberized nylon suit, and sealing the seams tomake it airtight. Alternatively, a compression sleeve may be connectedto the rubberized nylon exterior suit, by placing each over anappropriate diameter steel band, and then clamping together the twolayers of material with another outer ring. A standard air intakefitting can be installed in the pants to provide a port for pressurizingthe suit.

Another important aspect of the assisted motion system 10 of FIG. 1 isthe external support structure 26 that is necessary for preventing thedownwardly directed force F_(s) on the suit created by the positivepressure differential ΔP, from forcing the suit down and off therunner's body. In the case of FIG. 1, the embodiment of external supportstructure 26 constitutes a frame 28 and wheels 30 for providing completemobility to runner 12. Such support structures should be designed forthe specific range of body motions that the person wearing the suitplans to carry out.

Shown in greater detail in FIG. 20 is a wheeled frame structure 130 forsupporting a differential pressurized suit 132 worn by a runner 134 whois running. As the runner wears this suit 132 supported by the wheeledframe 130 during his running routine, he experiences less weight on hisfeet, knees, legs, and lower body, because a portion of his body weighthas been offloaded by the upwards force F_(b) on the body created by thepositive pressure differential ΔP of the pressurized suit 132. Thedownward force F_(s) on the suit also caused by the positive pressuredifferential ΔP is transmitted to the support structure 130, and fromthe support structure to the ground.

The wheeled frame structure 130 shown in FIG. 20 has a constructionsimilar to a bicycle: a wheel in the front 136 and one in the back 138.The runner 134 is positioned midway between the wheels, and the spacebetween the wheels is sufficient to avoid contact with the runner'slegs. The rotational momentum of the wheels stabilizes the frame duringmotion, as with a bicycle. The wheeled frame structure 130 wraps aroundthe runner 134 at the waist/hip level. Note the absence of a seat,pedals, sprocket and chain that are normal to a bicycle. The frame 130is designed so that the runner 134 can swing his arms and hands whenrunning.

The pressurized suit 132, as described in other embodiments of thisinvention, will create a force along the vertical axis of pushing thebody up, with the reaction force being that of pushing the suit down.The latter is countered in this embodiment by offloading this downwardreaction force to the ‘bike’ wheeled frame structure 130, therebyeffectively delivering part of the runner's weight to the bike frame andthus to the ground through the wheels.

A mechanism 144 allows for both rotational and angular pivoting of therunner's torso during the motion of running. In this embodiment, themechanism simply consists of a flexible pleated material 140 surroundingthe region about the waist of the pressure suit, which may bend andtwist with the movement of the runner's torso. Other mechanicalmechanisms for this purpose may also be utilized.

The wheeled frame structure 130 has a mechanism 146 for steering thebike. In one embodiment of the steering mechanism, the movable frontwheel 136 is steered in a similar fashion to a bicycle, except insteadof long handlebars, cables 148 and a small steering wheel 150 are usedemploying well-known mechanical methods to implement steering. In asecond embodiment of the steering mechanism, a handlebar is brought backin reach of one or both arms of the runner. The only difference in thisembodiment and a standard bicycle steering mechanism is that a centeringspring holds the bike true, or non-turning until the runner appliesforce to the steering handle bar. This allows periods of running withoutactive steering. A third steering embodiment uses a stepper motor in thesteering column powered by an embedded rechargeable battery. Thesteering is controlled by the motor via a wireless handheld gloveactuator that provides motion commands to the motor using well-knownwireless and motion control methods. This permits the runner to freelyswing his arms in a natural running motion, and still retain full-timesteering control. A fourth steering embodiment positions the hub of thewheel backwards or forwards of the vertical axis of steering to provideautomatic steering.

The wheeled frame structure 130 may also have standard bicycle brakeswhich are operated by a hand lever using well-known means, or by thehandheld remote control method that may actuate electric powered brakes.

An optional constant force extension mechanism may be used that providesa constant upwards force on the pressure suit allowing it to movevertically with the vertical motion of the runner's body. The constantforce of the mechanism is adjustable so that the upwards force on themechanism is equal to the downwards force of the suit under pressure.The suit can thus float vertically up and down with the motion of therunner's torso, while maintaining an essentially constant upward forceon the suit. A range of motion of 0-7 inches is provided to accommodatevarious runners, with 3 to 4 inches being a typical verticaldisplacement in running motion.

Different frames sizes may be provided to fit different sized runners.The vertical position of the rotational and angular pivoting mechanismsand the constant force may be adjustable to accommodate different bodyheights.

An alternative embodiment to the foregoing bicycle-like running supportstructure 130 is a cart-like structure with four wheels, arranged aspairs of wheels lateral to the left and right sides of the runner, asshown in FIG. 21. In this embodiment, the wheeled frame structure 160 isconnected to each wheel 162 lateral to the runner, leaving a clear pathto the front and back of the runner. The front wheels operateindependently and are implemented as turnable castors 163 to accommodatesteering. The rear wheels also rotate independently, but are fixed ontheir vertical axis. The axle shafts 164 provide a rigid connection tothe interface member 166 for the pressure suit 168. In a manneridentical to the bicycle-like embodiment, a portion of the runner'sweight is off-loaded via the pressure suit 168, and transmitted to theframe, axle shafts 164, and ultimately the ground 172. Steering isaccomplished passively in that the cart simply follows direction changesengendered by the runner's change in direction, which translates twistthrough the frame to the front wheel castor mechanisms in a mannersimilar to steering a shopping cart.

Yet another embodiment may be that of a tricycle, where a pair of wheelsfront-left and front-right of the runner are connected to the frame asin the four-wheeled cart, and a third free wheel and a single freeturning rear wheel confers stability to the system. Finally, it shouldbe realized that any number of wheels may be used without departing fromthe scope of this invention.

FIG. 22 shows another embodiment of the support structure consisting ofa stationary supporting frame 180 positioned over a treadmill 182. Theframe 180 provides support for the pressure suit 184 worn by the runner186. Any of the aforementioned pressure suit embodiments may be utilizedfor this static support structure 180. For illustrative purposes, FIG.22 depicts a pressure suit 184 that ends above the ankles. Conceptually,the only difference between this static support structure 180 and theaforementioned wheeled frame structures 130 and 160 is that the reactionforce that is subtracted from the runner's weight is offloaded from therunner to a rigid fixed structure, the treadmill frame, instead of amobile structure.

This is accomplished by providing a set of sliding rods which supportthe runner and are arranged to allow for longitudinal and lateralmotion. A rigid waist loop supporting member 188 wraps around therunner's body and connects to the pressure suit 184 at the waist. Ahorizontal longitudinal sliding rod 190 connects to each end of theframe and slides through the fittings 192. The sliding longitudinal rodallows for longitudinal movement of the runner in the front to backdirection on the treadmill 182. The fittings 192 are attached at themiddle of each of two horizontally-disposed sliding lateral rods 194.These sliding lateral rods allow for lateral movement of the runner onthe track in the side-to-side direction. The lateral sliding rods 194slide through fittings 196 that are fixed atop adjustment mechanisms198. These adjustment mechanisms provide a counter-force to support thevertical downwards loads from the suit and sliding rods, while allowingfor the vertical downwards loads from the suit and sliding rods, whileallowing for the vertical motions of the runner 186. Preferably, theseadjustment mechanisms are air cylinders. They also preferably provideconstant force. In other embodiments, adjustment mechanisms may be airsprings or constant-force mechanical springs, as is known in the art.The adjustment mechanisms may also be mechanical springs or aircylinders or air springs that are not constant force. The springs areconnected to vertical rigid members 200 that connect to the base of thetreadmill.

In usage, the adjustment mechanisms are each set such that the totalforce equals the desired weight to be subtracted. Air cylinders areavailable from Bimba Manufacturing Company of Monee, Ill. Prior topressurizing the suit 184, the runner steps up on a small support aboutone foot above the surface of the treadmill, and clips into the hooks onthe air cylinder apparatus. Once this is done, the suit 184 may bepressurized. By standing on a scale, the pressure may be set to subtractthe desired weight. Alternatively, since the pants characteristicsshould be known a priori, a specific calculated pressure P applied tothe suit 184 will yield a specific weight subtraction. The desiredweight subtraction set via the pressure P, and the counter forcesupplied by the adjustment mechanisms 198 can be approximately matched.A control system can control the adjustment mechanisms 198 to providethe correct counter-force. During running, a runner could movevertically from 1 to 7 inches, typically 3 or 4 inches, verticallyrelative to the running surface. The function of the adjustmentmechanisms 198 is to maintain a constant offloading of the reactionforce dynamically, in response to this vertical displacement duringrunning.

Another embodiment of a constant force adjustment mechanism is shown inFIG. 23. An upper supporting ring structure 191 is connected to thecentral supporting structure 190 via a connection fixture 197. An aircylinder actuator 199 is attached to each side of the supporting ring191. Air cylinder actuators are available from Bimba ManufacturingCompany of Monee, Ill. The air cylinder actuator 199 consists of acylinder 193 and a piston rod 195. The piston rod of the air cylinderactuator is attached to the waist band 54 of the suit at the connectingeye 50. A control system can apply the correct calculated pressure tothe air cylinder actuators. This adjustment system may also be employedon the various supporting frames described herein.

In contrast to large stationary pressure chambers known in prior art, asignificant advantage in this static support structure 180 is that itallows both lateral and longitudinal movement of the runner relative tothe treadmill track. Another advantage over large pressure chambers isthat the runner's arms can swing freely.

The motion assistance system of the present invention can also be usedto help bicycle riders minimize the effect of erectile dysfunction ornumbness caused by the pressure of the bicycle seat horn on the groinregion. Embodiment 210 of the invention shown in FIG. 24 reduces thecontact pressure between a bicycle rider 212 and the seat 214. Thisembodiment utilizes air pressure contained within a pressurized suit 216to apply an upward force on the bicycle rider to reduce or eliminatecontact pressure between the rider and the seat. The air pressureapplies an evenly distributed pressure on the pressurized suit 216 andlower body of the rider, which lifts the body to reduce the contactpressure between the rider and the seat.

The bicycle 218, itself, is utilized as the supporting structure tosupport the downwards force of the pressure suit. The bicycle seat 214provides a support point for the pressure suit. The pressure suit 216 ismodified to attach to the bicycle seat and prevent the suit from movingdown the body due to downwardly directed force F_(s) on the suit createdby the positive pressure differential ΔP. A reinforced rigid structureis incorporated into the pressure suit 216 to attach to the bicycleseat. The attachment allows for easy connection and disconnection as therider mounts and dismounts the bicycle.

As shown more clearly in FIG. 27, the rigid structure 228 has a band 225that extends around the rider's waist. Another rigid band 227 from theback of the rider and through the crotch to connect to the frontsection. The bottom crotch section 226 is shaped to conform to therider's anatomy and the surface of the bicycle seat.

FIG. 24 shows a side profile of a bicycle rider wearing the pressurizedtrunks. The pressurized suit 216 is utilized to subject the lowerportion of the rider's body, below the waist and the upper legs to apressure P greater than atmospheric pressure P_(atm). The close-fittingpressure suit 216 is constructed of layers of materials which maintainthe pressure and prevent the suit from expanding circumferentially orlongitudinally. The pressure suit has an airtight seal 222 against thebody at the waist. The suit extends to above the knees. Alternatively,the pressure suit may extend to the ankles or around the foot. Thebottoms of the legs of the pressure suit have airtight seals 224 againstthe legs above the knees. In an alternative embodiment, the suit mayhave a pleated portion at the hip joints similar to the design ofconstant volume joints in the loose-fitting pressure suit. The pleatedjoint includes a tension strap on the rider's side from the waist to thelower part of the leg of the suit which prevents the pleats from fullyexpanding when the suit is pressurized.

The suit is pressurized to pressure P which is greater than atmosphericpressure, thereby creating a positive pressure differential ΔP in thesuit. The positive pressure differential ΔP results in anupwards-directed resultant force F_(b) on the body located at thecentroid of the cross-sectional area A_(w) of the waist. A_(k) is thecross-sectional area of the spot on each leg just above the knee whereseals 88 engage the leg. The force on the body F_(b) is approximatelythe same as the force of the waist-to-just-above-the-knee suit 80 ofFIG. 12. The amount of this upwards force F_(b) is:F _(b) =ΔP×(A _(w)−2A _(k)).

Alternatively, the bicycle pressure suit embodiment may also incorporatean inner airbladder (as previously described) to contain the airpressure, as a seal. The air bladder is made from a flexible materialsuch as neoprene and roughly the same shape as the bicycle pressuresuit. Another form of an air bladder is made from two sets of similarshaped airtight pressure suits, one inside the other and sealed to eachother at the waist and legs.

FIG. 25 shows a front view of the bicycle pressure suit. FIG. 26 shows arear view of the pressure suit. FIG. 27 shows a perspective view of thesupporting structure of the bicycle pressure suit. The suit has a rigidstructure 228 that fits snugly onto the bicycle seat 214. The structuremay be an exoskeleton (i.e. a structure outside the suit), or anairtight rigid portion that is part of the airtight suit. Theexoskeleton extends around the side of the body at the waist, andextends through the crotch and around the back side of the rider to jointhe frontal structure at the waist at the rider's side. The rigidstructure is capable of supporting the downward load F_(s) on the suitcreated by the differential pressure ΔP. The structure is attached tothe suit at the crotch and at the waist of the suit. The rigid structurecontacts the bicycle seat when the rider is seated. The rigid structureis shaped to conform to the bicycle seat, and is also shaped to conformto the rider's body.

When the suit is pressurized to a pressure P, the positive pressuredifferential ΔP also results in a downwards directed resultant forceF_(s) on the suit 210. This downward force is transferred to the rigidstructure of the suit at the attachment points between the rigidstructure and the suit. The rigid structure supports this downwardtensile load on the suit and transfers the load to the seat. The rigidstructure effectively holds the suit up against the downward force F_(s)created by the air pressure. It provides the counter force that preventsthe suit from moving down the lower body when pressurized. When the suitis adequately pressurized, the body is effectively lifted off the seat.The lifting of the body reduces or eliminates the local pressure pointsbetween the rider and the bicycle seat. The rider literally floats abovethe seat supported by air pressure. There are no, or reduced, “pressurepoint” forces of the bicycle seat on the groin area of the rider. Thisprovides for increased riding comfort and reduces or eliminates the riskof injury to the rider,

Similar supporting structures and pressure suits to the ones shown inFIGS. 24-27 can be adapted for other exercising devices such asstair-masters, orbital trainers, and cross-country ski trainers.

In lieu of the wheeled or static support structure discussed above forthis invention that is separate from the pressurized suit, thesupporting structure component may be directly incorporated into thepressure suit so that both the supporting frame and the pressure suitand body have the same movements. In this manner the invention providesfor a wide range of movements and exercises over a variety of terrains.

As shown in the embodiment 230 of FIG. 28, the supporting frame is arigid exoskeleton structure 232 made of lightweight rods and joints thatis attached to the outside of the pressurized suit 234. The rigid frameand joints of the exoskeleton 232 provide the necessary support for thedownward force of the pressurized suit 234. The downward force of thesuit F_(d) is equal to the upward force F_(u) at the attachment point tothe top of the exoskeleton. The exoskeleton has matching supports on theinside and the outside of the legs.

The embodiment 240 shown in FIG. 29 is the same as that shown in FIG.28, with the exception that the rigid exoskeleton 242 is built into thefabric of the suit. The exoskeleton 242 comprises a number of relativelystrong thin vertical rods 244 that have a flexible joint at the knee.The rods are integrated into the air-tight fabric that comprises thesuit 234 as described earlier, and terminate uniformly at an ankle ring246 that in turn conducts the force to the exterior of the bootstructure and thus to the ground. Alternatively the rods 244 may belayered over the suit and suitably attached at a multitude of points.The rods generally follow the longitudinal lines of non-extension of thelower body and legs. The rods 244 are comprised of a suitablelightweight, but strong material such as aluminum or a compositematerial. The internal exoskeleton 242 supports the legs of thepressurized suit 234. It is depicted inside only one leg in FIG. 18 forease of understanding.

Another type of supporting device for the assisted motion system 10 ofthe present invention utilizes the air pressure of the pressurized suitto support the runner. In this case, no supporting frame is required.The column of pressurized air contained in the leg units is capable ofsupporting a load equal to the differential pressure ΔP times thecross-sectional area of the leg unit A_(u).

As shown in FIG. 30, in this embodiment 250 the body suit 252 consistsof tubular units 254 around each leg. The leg units have an equivalentor slightly increasing cross-sectional area from the top to the bottom.This shape of the tubular units 254 results in no vertical downwardsforce being imparted on the exterior of the tube by the internalpressure of the unit. The units are sealed at the bottom around thefoot. The units are sealed at the top against the thigh by seals 256, asdescribed previously. The units are sized, so that the column ofpressurized air can support the weight of the body that is supported bythe internal differential pressure ΔP. The load supported by each unitis equal to the cross-sectional area of the unit A_(u) times thedifferential pressure ΔP.

The positive pressure differential ΔP in the leg unit results in anupwards-directed resultant force F_(b) on the body located at thecentroid of the cross-sectional area A_(u) of each leg unit. The totalamount of this upwards force F_(b) on the body from a leg unit is:F _(b) =ΔP×A _(u).

As discussed with respect to FIG. 30 for the loose-fitting suitembodiment of the pressurized suit, constant volume joints 258 at theknees and 260 at the ankles allow the pressurized leg units 254 to bendand move with the walking and running motion without the need for undueforce. Loose fabric in these joints permit the volume to remainrelatively constant during bending. A retaining means between the loopsof fabric prevent the joint from expanding longitudinally when thetubular units 254 are pressurized. The person can conveniently exerciseon a treadmill 262.

In another embodiment, the tubular units may be shaped into forms thatenable the motion of the person wearing the suit 252, and provide for amore compact design. For example the tubular units may be ellipticalwith the longer axis aligned with the forwards-backwards axis of motion.The shape of the cross-sectional area can vary moving up and down theleg. The lower cross-sectional area can be shaped more like the lowerleg and foot. The upper cross-sectional area can be shaped like thethigh. This provides for a streamlined form, which does not interferewith the running motion.

Alternatively, the tubular unit may have a separate outer pressurizedchamber that provides the support. This chamber can have a higherpressure than required for providing support to the body to enablesupporting a higher load with less of a cross-sectional area for thetubular unit.

The unit may also have separate smaller pressurized tubular units whichsupport the load. Such an embodiment provides a more compact form closerfitting to the body.

The above described embodiments utilize an external mechanical support,exoskeleton, or the column of pressurized air to support the downwardsforce F_(s) on the suit. The ground directly supports each foot of theexoskeleton or air pressure support. For various exercises and movementswhere the feet do not to leave the ground, the suit can be staticallypressurized as has been previously described. However, for exercises andmovements where one or both feet leave the ground, once a foot leavesthe ground the downwards force of the pressure suit will tend to drivethe suit leg down off the leg. Therefore, these types of movementsrequire a cyclical pressurization and depressurization of the suit whenthe leg contacts and leaves the ground respectively may be done. Thiswill provide effective off-loading of body weight when the leg is inground contact, and prevent the suit from moving down the leg when it isnot in contact with the ground.

FIG. 31 shows an embodiment of the invention in which the suit extendsto the waist. The seal 298 positioned between the body and the outsideair pressure is at the waist. This seal has an opening that is smallerthan the waist, and fits tightly to provide an airtight seal underpressure. Alternatively, the seal can consist of tight-fitting, airproofcompression shorts. A constant volume joint at the waist 296 allows thebody to bend and move at the waist and hips with the motion of walkingand running without undue force. The leg pressurization compartmentsextend to the waist unit, so that the waist is divided into twopressurization compartments, one corresponding to each leg. Theadvantage of this design is that by extending the compartment to thewaist, a larger cross-sectional area is available to have a pressuredifferential across. This approach also has the advantage of reducingstress on the hip joint, pelvic area, and lower back.

As shown in FIG. 31, the pressure in each leg of the pressurized suit272 is independently controlled such that the suit or a portion of thesuit may be depressurized. In the phase of running depicted in FIG. 31,with the supporting leg 274 on the ground and the non-supporting leg 276leaving the ground, positive pressure is applied to the supporting leg274 while the non-supporting leg 276 is depressurized. Cyclicpressurization is accomplished with a control system 278 andpressurizing unit 280 to which is operatively connected a source ofpressurizing gas 282. Sensors 284 and 286 under each foot sense eitherapproaching foot strikes or incipient foot contact, and they signal thepressure unit 280 when to pressurize the appropriate leg member 274 or276. Just prior to or upon lifting of the foot the leg member isdepressurized, thereby allowing the leg to freely release from theground for the return or “float” phase of the running cycle.

The pressurizing system 280 consists of an air pressurizing unit andpressure hoses 288 connected separately to each leg. The leg units canbe pressurized to pressures P₁ and P₂ which is greater than atmosphericpressure P_(atm). When depressurized the pressures P₁ and P₂ may beequal to or even less than P_(atm) air. Each leg unit 274 and 276 ispressurized and depressurized separately. The cross-sectional area ofthe leg unit over its length is sufficient to support the weight that issupported by the air pressure. The cross-sectional area may beessentially constant, or may be increasing towards the floor.

A treadmill 290 provides for a moving surface to enable walking andrunning. The units may also be used with other exercising devices suchas a stair-master, an orbital trainer or a stationary bicycle. Constantvolume joints are provided at the knees 292, ankles 294, and waist 296to facilitate bending of the suit 272 when it is pressurized asdiscussed above.

In operation during a walking/running motion, each leg unit ispressurized as the foot is placed on the ground, and depressurized whenthe foot is removed from the ground. A control system monitors themotion of the body and controls the pressurization and depressurizationof the leg units. The control system consists of sensors 284 whichdetect when the leg-unit is about to contact the surface, and othersensors 286 which detect when the foot is leaving the ground on thereturn phase of the running cycle. The sensors may sense either pressureor the distance from the foot to the ground. The control system 278pressurizes the leg unit which is on the ground (or just about tocontact the ground) using a pressurizing unit 280 connected withsufficiently large pressure capable hoses 288. The pressurizing unituses an electro-pneumatic regulator to change the pressure upon a signalfrom the control system. The pressurizing unit 280 and hoses 288 aresufficiently sized to pressurize and depressurize the units very quicklyso that force on the leg is reduced immediately upon placement on theground.

The operation of the invention is as follows: at the beginning of awalking or running step the foot being returned makes contact with theground. Sensors on the foot determine when the foot is making or aboutto make contact with the ground. When the foot contacts the ground, apressure sensor 284 detects an increased force on the outer foot of theleg unit. The sensor might also be a distance sensor such as an infraredsensor which detects the distance between the outside foot of the unitand the ground. Air pressure is applied through the control device suchthat when the foot makes contact with the ground (or is about to makecontact with the ground) the unit is pressurized. The pressurizationreduces the muscle-skeletal stresses from contact on the leg and lowerbody. The pressure is maintained throughout the step. Furtherenhancements to the control system can be made so that pressure isincreased or reduced to enhance movement.

At the end of a walking or running motion, the foot is lifted off of theground for the return. When the foot is lifted off of the ground, apressure sensor 286 detects a reduced force on the inner foot of theuser. The sensor might also be a distance sensor which detects increasedspace between the foot and the bottom of the leg unit. The controlsystem depressurizes the leg unit as the leg is lifted off of theground. Instantly depressurizing the unit removes the force of thepressurized leg unit on the ground. This allows the unit to be raisedoff of the ground during the return without a force either ejecting theunit from the leg or interfering with the return or float phase of therunning cycle. Depressurizing the unit for the return also reduces thebending force required on the constant volume joints during the legreturn.

In another embodiment 300 of the invention shown in FIG. 32, thepressurizing unit and control system are portable. The pressuring unit302 is attached to the back of the user and delivers air pressure topressure suit 304 via hoses 306. The unit is powered to generate airpressure. Power to the unit is supplied through a battery-driven motoror gas-driven engine. Similar power units have been developed formechanically operating pressure systems.

In this case, the pressure suit 304 covers the feet and reaches theupper thighs. A seal 308 around the top of the suit contains thepositive air pressure contained inside the suit. Exoskeleton 310attached to the exterior of the suit provides the necessary support tothe pressurized suit. Sensors 312 and 314 positioned on the bottom ofthe feet of the suit allow the control system to cyclically pressurizeand depressurize the legs of pressure suit 304 to facilitate the walkingor running motion as described above.

Portability allows for walking, running, or exercising anywhere. Runnersand walkers for example can exercise outside. The system 300 may bedesigned to enable backpackers and soldiers for example to move fasteror carry heavier loads.

Portable pressurizing systems can also apply to other types of pressuresuits that utilize a pressurizing mean other than pressurized air. Forexample, pressure suits that use such as shape-memory materials as thepressurizing device could utilize an electric current applied to thematerial which would create the pressure.

In another embodiment 320, the cycle pressurization mechanism isincorporated directly into the foot section of the suit, as shown inFIG. 33. The suit is composed of a close-fitting suit attached to anexoskeleton as described above. A foot driven air pump 322 is providedon the bottom of the foot. Pump 322 a is shown on the left footcontacting the ground, while pump 322 b is shown on the right footleaving the ground. The pump is compressible with baffles and a springreturn. The bottom end of the exoskeleton 310 is connected to the bottomof the air pump. When the foot is placed on the ground during a walkingor running, the pump 322 a is compressed, thereby delivering pressure tothe suit. When the foot leaves the ground during the end of the stride,the pump 322 b expands, and air flows back from the suit into the pumpautomatically depressurizing that leg of the suit. The foot pump issized to provide the correct amount of pressurization. This system isautomatic and does not require any outside pump or control devices.

For the suits described which provide exoskeletons as the supportingstructure, the movement of various body movements can be furtherenhanced by using a powered exoskeleton, as is known in the art. Apowered exoskeleton consists primarily of a skeleton-like framework wornby a person and a power supply that supplies at least part of theactivation-energy for limb movement. Typically, a powered exoskeleton isattached at specific localized points of the body through mechanicalmeans. These local mechanical pressure contact points on the body aredeleterious. The use of differential pressure to support the body allowsfor the coupling of the exoskeleton to the body to be distributed over alarge body surface.

The concept of supported differential pressure can be utilized toun-weight other areas of the body. For example, by creating a pressuredifferential between the narrower waist or lower pelvis of a seatedperson using a supported differential upper body pressure suit, theperson's upper body weight can be unweighted. This could be used toreduce pressure on the lower back and spine for people with lower backpain, degenerative or ruptured disks, etc.

An example of this suit is shown in FIG. 34. The differentialpressurized suit 325 shown in FIG. 34 comprises a full-length suit whichextend to the chest area just below the arms. This embodiment of thesuit completely covers the feet, legs, and lower body. Alternatively,the suit may extend to the ankles, knees, or upper thigh. The suit issealed at the chest. The seal may constitute any of the sealing methodspreviously discussed, including a neoprene band, an inflatable tube, oran inflatable bladder. The suit is connected to a rigid band 326. Theband serves to attach the suit 14 to the supporting structure 327 whichin this embodiment is a chair. The connection is such that the personmay easily engage or disengage from the chair. The band 326 conforms tothe generally elliptical shape of the chest cross-section. The band andconnection to the supporting structure are sufficient to support thedownward force of the pressurized suit. Air-tight zippers (not shown)assist entry into the full length pressure suit. The suit can connectand disconnect to connection valve 329 on the chair when the person sitsdown or gets up from the chair. The connection valve 329 is connected toa pressure control system 328 that can pressurize and depressurize thesuit, as needed.

Supported differential pressure suits can also be utilized to supportthe body when it is in a horizontal position. The utility of thisapplication is that patients in bed can be supported solely bydifferential pressure. This allows air circulation for the purpose ofhealing and the prevention of bedsores, for example. It removes pressurepoints caused by the body being supported by a mattress or other solidsurface. For a person in a horizontal position, the pressuredifferential is created across a plane which splits the upper and lowerhalves of a horizontal body. This creates a large cross-sectional areaA_(h). An example of this embodiment is as shown in FIG. 35. The suit333 extends from the shoulder area to the upper thigh, and extendsvertically half way or more above the back of the person. In this case,the seal 330 separates the horizontal body between the upper and lowerbody halves. An air bladder, as previously utilized, is employed tocontain the pressurized air between the upper and lower halves.Alternatively, in another embodiment, air-tight seals are constructed toseparate the upper and lower body halves.

Rigid support structures 331 attached to or positioned on a bed 334support the suit against the downwards force on the suit created by thedifferential pressure. The utility of this application is that patientsin bed can be supported solely by differential pressure. This allows aircirculation for the purpose of healing and the prevention of bedsoresfor example. It removes pressure points caused by the body beingsupported by a mattress or other solid surface.

The pressure suit may be connected to the supporting frame in a numberof different ways: Straps on the pressure suit may be attached directlyto the frame. For instance, waist straps on a waist-high pressure suitmay wrap around the waist ring of a supporting frame. Another method isto have a fastener such as Velcro on the pressure suit which attaches toa mating fastener on the supporting frame. Mechanical snaps or similarfasteners may also be utilized as the attaching device. A lacing systemmay also be utilized where the suit is laced to the supporting frame.Elastic systems may be utilized in the connection between the supportingframe and the suit. For example, elastic straps may be used. Thisprovides flexibility between the suit and the supporting frame toenhance body movement.

Where the supporting frame is positioned significantly above the suit,for example for a pressure suit on a large mammal, the suit can beattached to an overhead supporting frame with a system of ropes.

The supporting suit can also be attached to the frame using a zippersystem. One side of the zipper is on the suit. The other side is onfabric attached to the supporting frame. The person then wears the suitattached to the supporting frame by zippering in.

Another method is to permanently fix the pressure suit to the frame. Theperson then simply enters the suit at the opening. For instance, asupporting suit with an opening at the waist can be fixed permanently toa ring of the supporting frame. The person simply enters the suitthrough this opening.

Another method is to incorporate a rigid band or other rigid structureinto the supporting suit. This rigid band is then attached to thesupporting suit by various mechanical fasteners. For example the rigidband can have snaps, which then snap onto the supporting frame. Thesupporting band can have custom fittings which nest into mating fittingson the supporting frame. A rigid structure can also simply rest on apart of the supporting frame. For example, the rigid structure in abicycle pressure suit can simply sit on the seat of the bicycle.

The suit may also be attached to the supporting frame with air pressure.An air pressure tube can be utilized which, when inflated, pressesagainst the supporting frame sufficient to support the suit.

Exoskeletons may be mechanically attached along the length of the suitusing mechanical fasteners such as snaps or Velcro. The suit can also bepermanently fixed to the exoskeleton. The exoskeleton can also be fitinto sleeves in the fabric of the supporting suit. The exoskeleton canalso be incorporated into the fabric of suit.

Various positive differential pressure embodiments have heretofore beendescribed in this application for the motion assistance system 10.Negative differential pressure utilizes the same essential principle ashas been described for the positive differential embodiments. Howeverthe use of negative differential pressure presents some uniqueopportunities for various anatomic positions of partial body suits.

A useful embodiment using negative differential pressure is described asfollows. In FIG. 36, a person is shown wearing a vest apparatus 350,wherein the vest is a hard shell material, with the strength to supportan interior partial vacuum relative to atmosphere of up to −2.0 psi. Toachieve air tightness, four seals are required: two arm seals 352, aneck seal 354, and a chest seal 356. The cross-sectional area of theneck seal is denoted A_(n), and for the chest seal A_(c). The seals arecomprised of airtight stretchable neoprene or latex sleeves connected tothe interior of the hard shell vest 350. The sleeves extend far enoughaway from the hard shell (along the neck, arms, or chest, respectively)to ensure a reliable seal. The entire vest apparatus 350 is thustopologically like a T-shirt; the primary differences are that the neckand sleeves are tight fitting to form seals, the main body is rigid, andthe bottom also forms a seal around the chest.

The hard shell vest 350 has a port 358 that connects to a vacuum hose360 which connects ultimately to a vacuum generator 362. In use, theinterior of the vest is depressurized to a partial vacuum pressure Prelative to atmospheric pressure P_(atm). This produces no net forces onthe body in the front-back direction, nor in the lateral (left-right)direction, due to symmetry. Following the identical convention that hasbeen previously described, the net upward vertical force is calculatedwith the following equation:F _(b) =ΔP×(A _(n) −A _(c))Note that since A_(c) is significantly larger than A_(n), the quantityin parenthesis will be negative. HoweverΔP=P−P _(atm)

This implies that ΔP will also be negative if P is less than P_(atm)which is the case where P is a partial vacuum relative to P_(atm). Themultiplication of these two negatives yields a positive F_(b), which inthis coordinate system is an upward, vertical force on the body. As inprior examples, the reaction force on the suit F_(s) will be equal inmagnitude and opposite in direction to F_(b), or downward. Counteractingor offloading F_(s) to suitable support mechanisms such as a treadmillframe or wheeled devices are identical in principle and very similar inpractice to the previously described positive pressure embodiments. Theuse of the two wheeled running device in conjunction with the vacuumvest 350 will be described as an exemplary, but not limiting embodiment.

The reason the vest in this embodiment only extends down to the chest(no lower than the sternum), and not to the waist, is so as not todisrupt the normal diaphragmatic distention in the abdomen, which isnecessary for unencumbered ventilation. Placing the abdomen in a staticvacuum would otherwise dispose the lungs toward inspiration, and wouldmake expiration more difficult, so it is avoided in this invention.

FIG. 37 shows the vacuum vest 350 in conjunction with the exemplarytwo-wheeled offloading apparatus 370. The wheeled apparatus is shown insimplified form with frame 372 and wheels 374. Brake and steeringmechanisms are omitted for the sake of clarity. The vacuum vest 350 isshown positioned on the upper torso. Note that no lower body apparatusis used in this embodiment. The runner's waist is loosely confined to aloop 376 in the frame 370.

As previously described, a neck seal 354, arm seals 352 (only one ofwhich is visible) and chest seal 356 are shown. Rigid members 380connect to snap fittings in the front and back of the hard shell vest350 down to the frame 370. This carries the downward reaction force ofthe vest F_(s) when under vacuum to the frame and ultimately to theground 382 through the wheels 374. Concomitantly, the runner 384 willexperience reduced weight due to upward force F_(b). As previouslydescribed, partial vacuum P is maintained in the suit by a small mobilevacuum generator 386 attached to the rear wheel. A vacuum hose 388 runinternal to the frame connects the vest 350 to the vacuum generator 386.The vacuum generator 386 is powered by a sprocket drive in tandem withthe rear wheel axle, using well-known gearing means. The vacuumgenerator may be preset to maintain a pre-determined pressure level inthe vest 350 so as to provide the desired amount of weight reduction forthe runner.

The motion-assistance system 10 of the present invention can also beused for non-human mammals. This has application in veterinary medicine,for example, for supporting injured horses or dogs that need weighttaken off of their lower legs. An embodiment with a moveable frame willallow the animal to exercise with a reduced load on its muscle skeletalstructure.

An embodiment of a differential pressurize suit 400 for a horse 405 isdepicted in FIG. 38. In this particular embodiment, the suit extendsfrom the midsection 420 of the horse to the ankles 422 without coveringthe hooves, and is sealed at the cannon (metacarpas) of each of the fourlegs. The suit 400 is a close-fitting multi-layer suit, as describedearlier. In this embodiment, the pressurized air is contained by meansof an airtight bladder 402, as previously described. The bladderconsists of an airproof inner layer 403 and outer layer 404. The twolayers are joined at the top and bottom of the suit to form an airtightbladder. When pressurized, the inner layer presses against the hide ofthe horse, and the outer layer presses against the outer constraininglayer of the suit. A frontal view of the bladder 402 is shown in FIG.39. The bladder 402 contains air at pressure P. The bladder may be usedfor the various embodiments of the pressure suits described herein,including a bladder that extends from the waist to around the foot, abladder that extends from the waist to the ankle, and a bladder thatextends from the waist to above the knee.

The midsection seal portion of the suit may include a rigid band 406.Zippers on the suit allow the suit to be easily put on and removed fromthe horse 405. In this manner, when the suit is pressurized with air topressure condition P, the pressurized air is substantially containedwithin the suit 400.

The net upward force provided by pressurized air contained within suit400 may be calculated as:F _(b) =ΔP(A _(m)−4A _(c))where ΔP is the difference in pressure level P inside the suit andatmospheric pressure P_(atm) outside the suit. A_(m) is thecross-sectional area of the midsection. A_(C) is the cross-sectionalcannon area of each leg.

Four-legged animals have a cross-sectional area at the midsection of thebody that is large relative to the weight of the animal. A small amountof positive pressure P can easily support the weight of a large horse asshown in the following example. Measurement and weight data is availableon Fumiro KashiWamura, Avarzed Avgaanorj and Keiko Furumura, “BaneiDraft Racehorses: Relationships among Body Size, Conformation, andRacing Performance in Banei Draft Racehorses,” J. Equine Sci, vol. 12,no. 1, pp. 1-7 (2001.). Average Measurements for two-year-old horsesare: body length BL=74.2 inches; chest width WC=32.4 inches; hip widthWH=26.5 inches; cannon diameter CD=3.4 inches, weight=1983.2 lbs Fromthis the cross-sectional area of the midsection A_(m) is calculated tobe 2185.2 square inches. The cross-sectional area of the cannon of thelower leg A_(m) is calculated to be 10.6 square inches. For a suit 400pressurized to a modest 0.5 psi positive differential pressure, theupward force on the horses body F_(b) is 1071.4 lbs. For a positivepressure differential of 0.5 psi, over 50% of the horse's body weightcan be taken off its muscle-skeletal structure. A 1.0 psi positivepressure differential could effectively take off all of the horse's bodyweight.

An embodiment of a moveable structure 409 for exercising a horse 405 isshown in FIG. 40. It comprises a cart-like structure with four wheels,arranged as pairs of wheels lateral to the left and right sides of thehorse. In this embodiment, the frame 411 is connected to each wheel 410lateral to the horse 405, leaving a clear path to the front and back ofthe horse by the horse. The front wheels operate independently and areimplemented as turnable castors 412 to accommodate steering. The rearwheels also rotate independently, but are fixed on their vertical axis.The pressure suit 400 is attached to the frame 411 by means of straps413. When the suit is pressurized, a portion of the horse's weight isoff-loaded via the pressure suit 400, and transmitted to the frame, axleshafts, and ultimately the ground. Steering is accomplished passively inthat the cart simply follows direction changes engendered by the horse'schange in direction, which applies twist through the frame to the frontwheel castor mechanisms in a manner similar to a steering a shoppingcart.

A challenge posed by the pressurized suit of the present invention isproper management of the balance between the downwards force of the suitand the upwards force applied by the previously described constant forceadjustment mechanism, support structure, or other offloading means. Inparticular, the forces must be balanced when the suit is pressurized ordepressurized. If the force developed by the downwards force of the suitand the counter force applied by the constant-force adjustment mechanismare not applied simultaneously, the result will be imbalance of thedownwards force of the suit and the upwards force of the offloadingmeans. Thus, if the air pressure is applied first, the unopposeddownward force will drive the suit downwards. Conversely, if the upwardcounter tension force is applied first, then the suit will be pulledupwards. If however, the two forces are applied so as to continuouslycounter-balance each other, then the suit will remain in its correctposition on the person's body.

A method for smoothly applying the pressure and the offloading counterforce to the person wearing the pressurized suit will be described. Theapplication to pressure pants is used for exemplary purposes only, for asimilar system may be applied to the other embodiments of the invention,including the suit using negative differential pressure. The preferredmethod of an adjustable, but approximately constant-force spring will bedescribed. Following that, a mechanism to create a set point for acontrol algorithm will be described.

As described above, it is important over small vertical displacements inthe range of a typical runner (nominally 3 inches) that the counterforce is maintained approximately constantly. A variation of no morethan five pounds of force over three inches is preferred. This isreadily accomplished with stretch (bungee) cord material ofapproximately four feet in length, with a spring constant of 10 poundsper foot. Note that two cords are preferably used: one on the left sideand the other on the right side of the person. Thus a 40 pound maximumforce on each cord will yield an 80 pound offloading maximum. To achieve40 pounds on each side, the stretch cord will be stretched to twice itslength, or four feet of displacement. Note that the 3 inch (0.25 feet)vertical displacement of the person during running will cause 2.5 poundsof force loss on each cord at the peak height, for a total of 5 pounds,which meets the preferred minimum variation.

In FIG. 41, a pressurized pants implementation is shown depicting thestretch cord connected to the runner's left side. The right side cord isomitted for the sake of clarity. The cord 800 clips onto the pants onone end, and it goes up over a pulley 801 mounted above the person overthe treadmill apparatus. At the end of stretch cord 800 is an electronicload cell 805 capable of measuring the desired tension for 0 to 50pounds, and on the other side of the load cell 805 is a non-extensiblecable 806 of about four feet in length, but wrapped around a winduppulley 807. The windup pulley 807 is motor driven with a stepper orservo motor under system microprocessor control.

In parallel with the primary stretch cord 800 is a secondary cord 810whose purpose is essentially for measurement and control. Cord 810terminates at a fixed location 811 near pulley 801, and its initialsection is a short spring 812 with a spring constant of one pound perfoot, followed by an inline control load cell 813, a non-extensible cordsection 814, and a hand-operated ratcheting pulley 815 mechanism. Thelower end of 815 terminates in a non-extensible rope 816 that attachesto the pants.

The input controller keypad and display 817 contains a microprocessor.The microprocessor receives digitally converted inputs from the loadcells 805 and 813 and the pants pressure sensor 818. The microprocessor,in addition to standard I/O functionality for the treadmill, alsocontrols the pants pressurizing valve and a counter tensioning windupmotor.

At startup, the individual when ready begins with a START command to theinput control pad 817. After standard checks to ensure that inputs arebeing received from the load cells 805 and 813 and pressure sensor 818,the system instructs the user to tension ratcheting pulley 815 until the1 pound set point (plus/minus a suitable tolerance) is attained. Whenattained, a READY status is reported on the display, and the user stopsmanually tensioning. The primary tension cable 800 is tensioned viaactuating the windup pulley 807 until a slight decrease in the controlload cell is detected, and then it is paused at this setting. The userthen enters on the keypad 817 a target body weight to be offloaded bythe system. At this point, the air flow is initiated to generatepressure within the suit and the measurement from load cell 813 ismonitored in the control software. As soon as load cell 813 registers aforce increase, incremental tension is applied by turning windup pulley807 again to maintain the set point on the control load cell 813 at onepound. Subsequently an increment of air flow may be applied through airinlet hose 819, followed by incremental counter tension by actuatingwindup pulley 807 so as to maintain the one-pound set point on thecontrol load cell. In the simplest embodiment, this back and forthiteration may proceed until the desired target weight is achieved onload cell 805, or the maximum system allowed pressure is reached asreported by pressure sensor 818.

More sophisticated control algorithms may also be used for purposes ofthis elastic suspension system of the present invention, such as aproportional-integral-derivative (PID). The key aspect is that thecontrol parameter as reported by load cell 813 is increased by the airpressure system, whereas it is decreased by the counter tensionmechanism, and the control algorithm operates on both systems tomaintain the desired set point of the control parameter. When the userbegins running, the system may not need to monitor and perform furtheradjustments. However, by monitoring the cyclic peak values reported byload cell 813, on-going adjustments may be made to maintain the desiredset point.

Another method for pressurizing the pants and applying the counter forceincrementally may be performed as follows, again referring to FIG. 41.This method does not rely upon secondary load cell 813, or an associatedsecondary cable and tensioning device. Rather, it relies upon makingincremental and alternating steps of pressure and counter tension. Theuser begins by entering on keypad 817 a target weight to be offloaded bythe system. At this point, the air flow is initiated to generatepressure within the pants, and the measurement from load cell 805 ismonitored in the control software. The pressurized air is allowed toflow into the pants until load cell 805 registers a small suitableincrement, nominally one pound. Then pressurized air flow is stopped,and the counter tensioning is applied by turning windup pulley 807 untilan additional pound is registered on load cell 805 (now two poundstotal). Note that while the initial force created by the air pressurewill have driven the pants down the body by a small increment, theidentical force magnitude in the opposite direction created by thecounter tensioning device will return the pants to their startingposition. Next, pressurized air flow is initiated again, and the loadcell 805 is monitored until another pound increment is registered onload cell 805 (now 3 pounds), the air is shut off and again countertensioning is applied to match that increment with another one pound(now 4 pounds total on load cell 805). This iterative process may beperformed rapidly and repeated until the target weight offloading isachieved as registered on load cell 805.

While these embodiments of the elastic suspension system have beendepicted with respect to a stationary treadmill located indoors wherethe control unit can be mounted above the person exercising on thetreadmill, it is important to appreciate that portable systems employingthe electro-mechanical principles of this invention can be used as well.For example, a similar system could be mounted to a bicycle frame tomanage the countervailing pressure and support forces applied to thepressurized suit worn by the bicyclist. It is also important toappreciate that this elastic suspension system is not essential to useof the pressurized suit of the present invention.

A further use for a mobile pressurized suit is as a support aid that canbe used to assist the mobility of elderly or physically-impaired peopleundergoing rehabilitation, particularly those recuperating from leg orback injuries. The four-wheeled cart-like support structure 900 of FIG.42 is utilized as a wheeled walker, commonly called a “Rollator.” Theabove-described wheeled walker is also advantageous for those impairedpersons with limited or no use of their hands and arms. When thepressurize suit of the present invention 901 is worn by such a person,the support aid provides the necessary support for that person insteadof him having to resort to his arms and hands leaning on a conventionalwalker.

The support aid's frame 902 and front wheels 903 and rear wheels 904 aredesigned and sized so that the mobile unit has the functionality ofstandard wheeled walkers. The front wheels turn and pivot to allow foreasy turning. All four wheels may also turn and pivot. Typically thewheels 903 and 904 are at least seven inches in diameter—preferablyeight inches—to ensure better reliability. A three-wheeled walker mayalso be utilized. Moreover, to enhance the safety, convenience, anddurability of a wheeled walking aid and its parts, the wheeled supportaid may utilize tubular seats, back seats, and baskets with spacers andcushions.

The wheeled support aid can be incorporated with hand-operated brakelevers 905 and brakes 910. The brakes on the wheeled support aid mayconstitute locking brakes to allow the person to stand while supportedin a stationary position. Other means of braking may be provided forthose with limited use of their arms and hands. The wheeled support aidcan be designed to enable greater range for rotating the body from sideto side to enable the person in the wheeled support aid to turn fromside to side and stand facing one side or the other, or even the back.It may also have a seat that will allow for resting. The wheeled supportaid will have adjustable height. The wheeled support aid may also bedesigned with a folding mechanism for compact storage.

The wheeled support aid can feature hand supports for assisting theentry and exit from the support aid. The wheeled support aid can beconstructed from light-weight materials such as aluminum or composites.The pressure-assisted wheeled support aid may preferably use tubularseats, back seats and baskets with spacers and cushions. The wheeledsupport aid can be equipped with a source of pressurized air to controlpressurization of the suit, and means for balancing the downwards forceof the suit automatically as the pressure is adjusted.

The impaired person 911 wears a pressurized suit 900 that attaches tothe frame of the walker at attachment points 907. The various attachmentmethods previously described may be utilized. The previously describedconstant-force adjustment mechanisms may also be incorporated. Forwalking applications, there is minimal up and down vertical motion ofthe walker compared with a running motion, so less overall adjustmentand force balancing is needed for this embodiment. Various embodimentsof the pressurized suit 901 described earlier can be utilized with thiswheeled support aid. The suit can be customized for easy entry and exitby physically impaired persons. In particular the pressure suit can haveextra long zippers 908 and an easy entry supporting ring which makes thesuit easy to put on for a physically impaired person.

In addition to injury rehabilitation and cardio training, thepressurized suit of the present invention can also be used withbeneficial results by a person looking to lose weight. In order to burnfat through physical exercise the medical community advises that theperson's heart rate needs to be maintained within a specified range,usually lower than the heart rage for cardio training. Many peoplesignificantly overshoot this heart rate range for fat burning, resultingin a failure to lose desired amounts of weight. This disappointmentoften causes people to quit their exercises because of their difficultor unpleasant nature, and rely instead upon extreme diets.

The pressurized suit of the present invention, when properly used,enables the person to reach an elevated level of physical exercise witha significantly reduced heart rate. This should make it easier for thatperson to maintain her heart rate within the prescribed range for fatburning, and enhance the likelihood of achieving her weight reductiongoal.

EXAMPLES Example 1

A working model of pressure shorts (waist to above the knees) to reducethe effective body weight of an individual was constructed and tested asfollows. Shorts were sewn using airproof, rubberized nylon material(Harris Canvas, Minneapolis, Minn.), following a standard shorts patternwith legs extended to reach just above the knees. Seals were createdabove each knee by obtaining commercially available compressionleggings. The leggings were made airtight by applying a complete coat ofseam sealer (Seam Lock sold by REI, Inc. of Sumner, Wash.). The leggingswere worn by the test individual from mid-thigh, and they terminatedjust above the knee joint. Each legging was interfaced to a leg of thenylon exterior shorts by placing each over a 7″ diameter steel ring, andthen clamping together with a worm gear of said diameter. This was donefor expediency. In a commercial application, this union would simply besewn together, and seam sealed. The waist seal was constructed using apair of airtight, skintight, neoprene interior shorts. The waist ofthese inner shorts and the waist of the outer rubberized nylon shortswere sewn together and seam sealed to form an airtight seal. This ovalwaist-sized seal was sandwiched between a pair of boards, each 16″×28″with a 11.5″×15″ oval cut-out to allow a person to ‘climb in’.

An air intake fitting was installed in one leg of the outer nylonshorts. Once an individual placed himself in the apparatus, air pressurewas applied to the air fitting, and air pressure was monitored via asecond pressure port in the pants, using a high fidelity electronicpressure transducer. The oval board affixed to the shorts was clamped tovertical stands that rested on the ground. Thus, consistent with earlierdescriptions of this invention, air pressure, when applied, will tend topush the individual up, with the reaction force on the pressure shortstending to push the shorts down. The reaction force was countered inthis case with the vertical stands that fix to the oval board and thusto the pressure shorts. Thus, the reaction force was effectivelycommunicated to the ground. A weighing scale was placed beneath theindividual to record his weight as a function of the applied airpressure to the pressure shorts.

The expected weight reduction was calculated as follows: the crosssection of each leg just above the subject's knee was estimated, basedupon circumferential measurements, to be 15 square inches, for a totalof 30 square inches. The area of the waist ellipse was measured as 78square inches. Thus the vertical area differential was 48 (i.e., 78-30)square inches. This implies that 1 PSI would provide a lift, or weightreduction of 48 pounds. As shown in FIG. 43, the slope of the linearregression of the experimentally obtained and plotted data was 51.5pounds/pounds-per-square-inch, or 51.5 square inches. This is excellentexperimental agreement, within 10% of the expected 48 square inchesobtained from the cross sectional area estimations.

Example 2 Prototype Pressurizing Suit

A prototype pressurizing suit extending from the waist to around thefeet having an air bladder-type seals was constructed. The suit wasconstructed of two neoprene waders sized large and extra-large. Theneoprene waders were both waterproof and airproof. The smaller waderswere placed inside the larger-sized waders. The waders were fastenedtogether at the waist using an epoxy adhesive to form an airtight seal.This formed an airproof compartment between the outer wader and theinner wader, which could be pressurized. When pressurized, the innerwader formed a seal against the body; the outer wader formed thepressurized body suit. An automobile air valve was attached to the outerwader to allow the unit to be pressurized.

The body suit was pressurized using a standard air compressor. A hosefrom the air compressor was attached to the valve in the suit. Whenpressurized, the user could feel pressure on his legs and reduced forceon his legs. Movement was possible without lifting the legs from thefloor.

The suit was fitted upon a larger user, and the pressure was increased.The pressure was increased sufficiently such that the user's weight wasbeing totally supported by air pressure. The user's feet were off of thefloor. Movement was possible without lifting the feet from the floor.

Example 3 Pressurized Leg Unit

A pressurized leg unit extending from the thigh to around the foot wasconstructed. The unit was constructed as follows: A waterproof hip waderwas fitted tightly over a section of plastic PVC pipe. The pipe had aninner diameter slightly larger than the user's thigh. An airtight sealwas formed between the leg and the neoprene. On the top of the unit, aninner seal was formed by applying neoprene to the inner diameter of thePVC tube to a sufficient thickness, so that a tight airtight seal wasformed between the neoprene and the user's thigh. A pressure hosefitting was attached to the PVC pipe to allow the unit to bepressurized. The unit was pressurized to less than 3 psi. The pressurewas sufficient that the user noticed a reduction in weight and pressureon his foot.

Example 4 Cyclically Pressurized Suit

A proof of concept of a hip-length, dynamically-pressurized pant wasconstructed. A rubberized nylon pant was sewn, including an integratedfoot section large enough to accommodate the runner's bare foot inside.To create a thigh seal, a compression pant sleeve was sewn interior tothe pant around the thigh opening, and made airtight with seam sealer inthe form of Seam Lock sold by REI, Inc. of Sumner, Wash. Compressionsleeves were sourced from Advanced Brace of Irving, Tex. Thus anairtight compartment was made when the test subject's thigh was put intothe pant. A standard air intake fitting was installed in the pants, aswas a high-fidelity pressure transducer (ACSX05DN sold by Honeywell,Inc.). An air supply system with a solenoid controlled intake valve andexhaust valves (SCM Inc.) were connected to the air intake port. Thesolenoids were independently controlled from a computer controlleddigital I/O system (Phidgets Inc.), and in addition the computer had thepressure transducer signal input into an analog-to-digital converter(Phidgets). An “electric eye” was implemented, using a photo electricdriver-receiver pair (C18P-AN-1A sold by Automation Direct). The eye wasaimed such that the optical beam would break and trigger a logic signalgoing into the digital I/O signal when the subject's foot was just abovethe treadmill surface. A software program in the computer was written toactuate the intake and exhaust valves and thus dynamically pressurizethe pant as follows. During forward (float) motion of the leg with thepant, the exhaust valve was maintained open and the intake valve wasclosed. When the subject's foot was just above the treadmill surface(about 100 ms before contact), the photoelectric signal would trigger alogic one, and the computer program would actuate the states of the twovalves to reverse, such that fairly high air flow (20 psi nozzlepressure) was allowed to fill the pant until the pressure transducerregistered 1 psi. This created the un-weighing portion of the cycle forthis leg, which was maintained until the subject had moved forward towhere his leg was behind him and about to come up off the treadmillsurface, when the exhaust valve was opened. During the subsequent returnphase of the leg with the pant, since it was now depressurized, flexureat the knee was easy. It was verified that with 1 PSI of pressure, over80 pounds of net upward lift was created, and with somewhat more airpressure, a 135 pound individual was completely levitated.

Example 5 Pressure Suit with Inner Air Bladder, Inner and OuterConstraining Layers, and a Constant Force Support System

A working prototype of the pressurized suits with inner and outerconstraining layers and an inner air bladder shown in the embodiments ofFIGS. 3-4 and 14 was constructed and tested for performance as follows:

An inner air bladder was constructed in the form of a pair of inflatablepants for containing the pressurized air introduced therein. The pantswere constructed from latex sheeting with a thickness of 0.016 inches(0.4 mm). Such sheeting is available from Envision Design of San Jose,Calif. A pattern for a pair of men's pants available from HancockFabrics (www.hancockfabrics.com) was used for the design of these pants.Two identical pairs of latex pants were constructed from the patternusing standard known methods for constructing latex clothing. With onepair of pants inserted inside of the other, the inner and outer pantswere glued together at the waist and ankles to form an airtight pair ofcomposite pants. A valve was attached at the side of the pants to allowfor inflating and deflating the pants.

The inner and outer constraining layers were constructed as follows: Astandard pattern for a pair of men's tights was used for the design ofthese layers. Such patterns are available from Hancock Fabrics. Thepatterns were sized to provide a tight fit to the legs. The patternswere scanned into a computerized CAD clothing design system. Thelocations for lines of non-extension for the lower body and legs wasobtained from the published paper A. S. Iberall, “The ExperimentalDesign of a Mobile Pressure Suit,” Journal of Basic Engineering (June1970). The lines of non-extension were drawn in the CAD system toindicate the needed orientations of the fabric The circumferential linesof non-extension that were essentially perpendicular to the leg weredrawn on the pattern for the inner layer, and the longitudinal lines ofnon-extension that were parallel to the leg were drawn on that leg forthe outer layer.

Using the CAD system, the pattern was sectioned into pieces so that theorientation of the lines of non-extension were maintained. The sectionswere cut from the fabric to maintain the required direction ofnon-extension for each section. A two-way stretch fabric was used forthe fabric material. Such material is available from Schoeller TextileUSA of Seattle, Wash. Such fabric stretches primarily along onedirection and has minimal stretch in the perpendicular direction.Sections were cut and sewn together using standard sewing equipment.Zippers approximately 8-inches long were attached to the innerconstraining layer at the ankles to allow the suit to be pulled onto thebody. A band of fabric 1.5-inches wide was sewn around the outer layerat the level of the hip to form a slip to hold a rigid waist band. Theinner layer was attached to the outer layer at the position of the bandby sewing the two layers together. A rigid band was constructed ofaluminum strip I-inch wide by ⅛-inch thick. The band was formed into anoval shape to match the cross-sectional shape of the body at the waist.This band was fit into the slip of the outer layer fabric, and the endsof the band were attached together to form an oval loop. Foam padding1-inch wide by ¾-inch thick was attached by adhesive to the fabric ofthe inner layer at the position of the rigid band. Holes were cut in theconstraining layers to accommodate for the valve.

An air pressure control system was constructed as follows: An airregulator with a range of 0-15 psi was used to manually control thepressure condition within the suit. A gauge with a range of 0-15 psi wasattached to the regulator to monitor this pressure. A standard aircompressor supplied high-pressure air to the regulator. Flexible ¼″ NPThigh pressure tubing was used to connect the outlet for the low-pressureair from the regulator to the valve in the suit. The air regulator,gauge, and tubing are available from McMaster Supply (www.mcmaster.com).

A constant-force mechanism was constructed as follows: eight-foot longsections of ½-inch stretch cord were utilized to provide a relativelyconstant force over the approximately 4-inch range of vertical motionthat the suit would experience during running. The stretch cords wereattached to each side of the rigid band at the location of the hip.These bands were passed through pulleys attached to supports positionedabove the system, and the ends were fixed to a solid support. Theattachment location of the end of the bands was chosen so that a forceof approximately 30 lbs was required to stretch the bands over thepulleys and down to the rigid band at waist height. A standard treadmill(model PRO-FORM 835QT) was used. Proform treadmills are available fromSears, Roebuck and Co. The treadmill was centered below the location ofthe constant-force mechanism.

The suit was tested on a male subject weighing 140 lbs with a height of5′6″. The test subject put on the inflatable latex pants and the innerand outer constraining layers. First, while in the suit, the subjectwarmed up by running for four minutes on the treadmill. The elasticstretch cords were attached to the rigid band of the suit. The subjectstood on a short stool until the suit was pressurized so that the bandswere not stretched until the force was balanced by the force from thepressurized suit. Next, the tubing of the air pressure regulation systemwas attached to the suit. The suit was pressurized to 0.7 psi. Thesubject's weight was measured and determined to be 30 lbs lighter atthis pressure. The subject was able to walk and then run easily in thesuit. The subject was able to jump up and down easily and experienced afeeling of lightness. At low treadmill speeds, the subject was able towalk easily. At higher treadmill speeds, the subject was able to runeasily. It was observed that the movement of the legs looked to be thatof a normal running gait. The subject reported that there was noimpairment to bending at the knees or hips. It was observed that theelastic suspension allowed for a normal back and forth twisting movementof the hips while running. The twist was approximately two inches backand forth from the centerline. The subject reported no discomfort fromthe pressure of the suit. In particular there was no discomfort aroundthe waist and pelvis areas.

The treadmill speed gradually was increased to a maximum of 10 mph. Thesubject was able to run at the maximum pace of 10 mph. The treadmillpace was then set at 6.5 mph. Wearing a heart monitor, the subject ranon the treadmill for a five-minute period at a steady rate of 6.5 mph.During this time, the subject's heart rate was measured and it was foundto be stabilized at 120 beats per minute. The subject ran at the samerate of 6.5 mph without the pressurized suit, and his heart rate wasmeasured to be 140 beats per minute, thereby indicating thatsignificantly less cardiovascular effort was required to run at the samepace when using the pressurized suit of this invention.

Example 6 Vacuum Suit

A working prototype of a vacuum vest as shown in the embodiment of FIG.36 was constructed as follows. A rigid conformal vest was constructedout of fiber glass. This was facilitated by procuring a mannequin with atorso size larger than the torsos of the intended human subjects.Following well-known fiberglassing methods, four plies of fiber weresuccessively layered over the mannequin torso, extending vertically fromthe level of the sternum to the neck, and laterally completely aroundthe torso from front to back. There were no arms or head on themannequin, and holes were left open at the location where arms would beand a hole was left at the neck as well. When the fiber glass vest wassufficiently hard, it was removed from the mannequin by making verticalcuts in the front and the back.

Aluminum brackets were used to reconnect the two halves during testing,after placing them on the test subject. Sealing for purposes of thistest was accomplished by simply constructing a rubberized jacket. Acotton turtleneck shirt was rubberized with liquid latex and allowed toharden. A zipper was sewn in to allow the garment to be easily donned.The human test subject donned the fiberglass vest first, then therubberized jacket. The jacket and vest had a hole drilled in the backfitted with a port to connect a vacuum hose.

An initial test of the vest confirmed that when vacuum was applied,using a standard shop vacuum cleaner, the jacket was drawn tightly bythe vacuum and subsequently no air was allowed to be drawn into thevest, creating a partial vacuum within the vest. A pressure gaugemeasured vest air pressure at −0.6 psi relative to atmosphere. Thepressure was limited by the ability of the vacuum generator. Therelevant cross-sectional dimensions for the given subject were estimatedto be 80 square inches and 30 square inches, chest and neckrespectively, or a 50-square-inch differential. The product of 0.6 psiand 50 square inches yields about 30 pounds of force. This force,exerted downwardly on the vest, was countered by connecting the vest onboth sides of the neck to two rubber stretch cords suspended from theceiling over the test treadmill. There was 30 pounds of upward force onthe body due to the vacuum.

The subject ran a treadmill protocol. The first 4 minutes were warm-up,followed by a rest, followed by 6 minutes at a speed of 6.5 mph(miles/hour) with the aforementioned weight of about 30 poundsoffloaded. The subject's heart rate stabilized at 120 BPM for at leastthe last two minutes. The subject was then depressurized to return tohis natural weight, and allowed to rest. Then a six-minute run wasperformed at 6.5 mph at his natural weight. His heart rate reached 140beats per minute before stabilizing over the last half of this run. Inaddition to the subject's self report of feeling much lighter whilerunning under vacuum pressurize, the heart rate data provided objectiveproof that his physiologic loading was significantly reduced relative tohis natural weight condition. The above specifications and drawingsprovide a complete description of the structure and operation of theassisted motion system 10 under the present invention. However, theinvention is capable of use in various other combinations,modifications, embodiments, and environments without departing from thespirit and scope of the invention. Therefore, the description is notintended to limit the invention to the particular form disclosed, andthe invention resides in the claim and hereinafter appended.

We claim:
 1. A system for assisting the motion of or supporting a bodyof a mammal having a body weight during a treatment procedure, suchsystem comprising: (a) a pressure-tight suit made from flexible fabricadapted to being worn over all or a portion of one or more of themammal's body parts consisting of the torso, leg, or arm, thepressure-tight suit having at least one opening adapted to be positionedaround the mammal's torso, leg, neck, or arm for accommodation by thepressure-tight suit of the covered body parts; (b) each opening of thepressure-tight suit having connected adjacent thereto a pressure-tightseal for operative engagement of the body part surface of the mammal;(c) inlet means in the suit for introduction of at least one source ofpositive pressure to an interior of the suit between the mammal bodyparts and the suit to create a differential pressure condition thereinbetween the positive pressure condition inside the suit, and a pressurecondition existing outside the suit; (d) rigid support meansincorporated into the suit for accommodating the movements of themammal's body, while counteracting a downwards force applied to the suitwhen it is placed under the differential pressure condition; (e) wherebythe differential pressure condition exerts an upwards force upon thebody to offload a portion of the weight of the body to the supportmeans.
 2. The assisted motion system of claim 1, wherein the rigidsupport means comprises at least one rigid support member and at leastone flexible joint to accommodate the body movement of the mammal. 3.The assisted motion system of claim 2, wherein the flexible jointcomprises a hinge or pivot point.
 4. The assisted motion system of claim2, wherein the flexible joint comprises flexible material.
 5. Theassisted motion system of claim 2, wherein the rigid support membercomprises a rigid rod.
 6. The assisted motion system of claim 2, whereinthe rigid support member is adapted to be approximately aligned with alongitudinal line of non-extension of a lower body or leg of the mammal.7. The assisted motion system of claim 1, wherein the rigid supportmeans comprises an exoskeleton connected to the outside of thepressure-tight suit.
 8. The assisted motion system of claim 1, whereinthe rigid support means comprises an exoskeleton built into thepressure-tight suit.
 9. The assisted motion system of claim 1, whereinthe rigid support means comprises a flexible tubular unit forming partof the pressure-tight suit adapted to surround a limb of the mammal'sbody that is made rigid when the source of positive pressure isintroduced into the flexible tubular unit.
 10. The assisted motionsystem of claim 9, wherein the tubular unit has a cross-sectional areathat slightly increases from the top of the tubular unit to the bottomof the tubular unit.
 11. The assisted motion system of claim 9, whereinthe tubular unit has a cross-sectional shape that is non-circular. 12.The assisted motion system of claim 1, wherein the rigid support meanscomprises at least one pressurized chamber separate from and connectedto the pressure-tight suit that is made rigid when a pressurized gas isintroduced into it.
 13. The assisted motion system of claim 1, whereinthe pressure-tight suit comprises multiple layers of material.
 14. Theassisted motion system of claim 13, wherein at least one layer comprisesan inner vent layer.
 15. The assisted motion system of claim 13, whereinat least one layer comprises an air pressure resistant layer.
 16. Theassisted motion system of claim 13, wherein at least one layer comprisesa fabric layer for restraining the downwards force applied by thepositive pressure source to the pressure-tight suit.
 17. The assistedmotion system of claim 13, wherein at least one layer comprises a fabriclayer for restraining a circumferential force applied by the positivepressure source to the pressure-tight suit.
 18. The assisted motionsystem of claim 13, wherein at least one layer comprises a fabric layerfor restraining a longitudinal force applied by the positive pressuresource to the pressure-tight suit.
 19. The assisted motion system ofclaim 1, wherein at least one layer of material within thepressure-tight suit is non-extensible along a first axis, and extensiblealong a second axis perpendicular to the first axis.
 20. The assistedmotion system of claim 19, wherein the non-extensible axis of thematerial in the layer is adapted to be oriented relative to the body tobe approximately aligned in parallel to the line of skin non-extensionof the body.
 21. The assisted motion system of claim 19, wherein thenon-extensible axis of the material in the layer is adapted to beoriented relative to the body to be approximately aligned perpendicularto the line of skin non-extension of the body.
 22. The assisted motionsystem of claim 1, wherein a first layer of material within thepressure-tight suit is non-extensible along a first axis, and extensiblealong a second axis perpendicular to its first axis, and a second layerof material within the pressure-tight suit is non-extensible along afirst axis, and extensible along a second axis perpendicular to itsfirst axis.
 23. The assisted motion system of claim 22, wherein thenon-extensible axis of one of the layers is adapted to be orientedrelative to the body to be approximately aligned in parallel to the lineof skin non-extension of the body, and the non-extensible axis of theother layer is adapted to be oriented relative to the body to beapproximately aligned perpendicular to the line of skin non-extension ofthe body.
 24. The assisted motion system of claim 22, wherein thenon-extensible direction of the material of the one layer does notcoincide with the non-extensible direction of the other layer.
 25. Theassisted motion system of claim 1, wherein the pressure-tight suitcomprises two tubular leg units having independent pressure conditionsadapted to cover all or a portion of two legs of the mammal, and thesource of positive pressure comprises a first positive pressurecondition that is introduced to a tubular leg unit of the pressure-tightsuit corresponding to a foot that is in contact with a hard surface, anda second positive pressure condition less than the first positivepressure condition that is introduced to a tubular leg unit of thepressure-tight suit corresponding to another foot that is removed fromthe hard surface, further comprising a controller for regulating thecycling between the first and second positive pressure conditionsintroduced to the tubular leg units.
 26. The assisted motion system ofclaim 25, wherein the pressure-tight suit further comprises at least onesensor adapted to be positioned below the foot of the mammal fordetecting when the foot comes into contact with the hard surface, or arelative distance of the foot with respect to the hard surface, suchsensor providing a signal to the controller to regulate the cyclingbetween first and second positive pressure conditions delivered to thepressure-tight suit.
 27. The assisted motion system of claim 1, whereinthe at least one source of positive pressure is provided by apressurized gas.
 28. The assisted motion system of claim 27, wherein thepressurized gas comprises air or a gas at a higher concentration than isnaturally found in air selected from the group consisting of nitrogen,carbon dioxide, and argon.
 29. The assisted motion system of claim 1,wherein the source of positive pressure is portable.
 30. The assistedmotion system of claim 1, wherein the at least one source of positivepressure is produced by energy adapted to be expended by the mammal. 31.The assisted motion system of claim 1, wherein the at least one sourceof positive pressure is produced by a foot-driven air pump adapted to beoperatively connected to a foot of the mammal.
 32. The assisted motionsystem of claim 1 further comprising means within the pressure-tightsuit for regulating an air temperature or a humidity level within thesuit.
 33. The assisted motion system of claim 1, wherein thepressure-tight suit adapted to closely fit the mammal's body parts. 34.The assisted motion system of claim 1, wherein the pressure-tight suitis adapted to loosely fit the mammal's body part.
 35. The assistedmotion system of claim 34, wherein the loose-fitting pressure-tight suitcomprises at least one joint for encompassing a joint within a muscleskeletal structure of the mammal.
 36. The assisted motion system ofclaim 35, wherein the pressure-tight suit joint is a constant-volumejoint.
 37. The assisted motion system of claim 1, wherein thepressure-tight seal is selected from the group consisting of an airproofelastic sleeve, an airproof band, an airproof pair of shorts attached tothe interior of the pressure-tight suit adjacent to a sealing location,an inflatable air tube seal, and an air bladder.
 38. The assisted motionsystem of claim 1 further comprising a bladder attached to an interiorof the pressure-tight suit adapted to be positioned between the suit andthe body part, wherein the positive pressure introduced into theinterior of the suit is contained within the bladder.
 39. The assistedmotion system of claim 1 for the mammal having an upper body and lowerbody and feet, wherein the pressure-tight suit is adapted to be sealedaround a dividing circumference between the upper body and lower body ofthe mammal, and is adapted to extend down the lower body to cover thefeet of the mammal.
 40. The assisted motion system of claim 1 for themammal having a waist and lower body and ankles, wherein thepressure-tight suit is adapted to be sealed around the waist of themammal, and is adapted to extend down the lower body to seal around theankles of the mammal.
 41. The assisted motion system of claim 1 for themammal having a waist and lower body and knees, wherein thepressure-tight suit is adapted to be sealed around the waist of themammal, and is adapted to extend down the lower body to seal around theknees of the mammal.
 42. The assisted motion system of claim 1, whereinthe pressure-tight suit comprises separate leg units, each leg unitadapted to be sealed around a thigh of the mammal, and adapted to extenddown a lower body to seal around an ankle of the mammal.
 43. Theassisted motion system of claim 1, wherein the pressure-tight suitcomprises separate leg units, each leg unit adapted to be sealed arounda thigh of the mammal, and adapted to extend down a lower body to sealaround a knee of the mammal.
 44. The assisted motion system of claim 1for the mammal having a chest and lower body and feet, wherein thepressure-tight suit is adapted to be sealed around the chest of themammal, and adapted to extend down the lower body to cover the feet ofthe mammal.
 45. The assisted motion system of claim 1 for the mammalhaving an upper body, wherein the pressure-tight suit is adapted tocover the upper body of the mammal.
 46. The assisted motion system ofclaim 45 for the mammal having an upper body and waist and neck andarms, wherein the pressure-tight suit adapted to cover the upper body ofthe mammal is adapted to be sealed above the waist and adjacent to theneck and arms of the mammal.
 47. The assisted motion system of claim 1,wherein the mammal to which the pressure-tight suit is adapted is ahuman.
 48. The assisted motion system of claim 1, wherein the mammal towhich the pressure-tight suit is adapted is a four-legged animal. 49.The assisted motion system of claim 1, wherein the treatment procedurefor the pressure-tight suit is selected from the group consisting ofexercise or training, rehabilitation of an injury or to assist mobility,reducing weight on a muscle skeletal structure of the mammal,maintaining proper posture of a muscle skeletal structure of the mammal,treatment for neurological or balance disorders, ambulation, andassisting mobility for the physically disabled.